Will breastfeeding your baby raise their IQ? When should you start potty training your toddler? Parents of young children often ask questions like these, as they’re eager to know the right way to parent. However, Emily Oster argues in Cribsheet that there isn’t just one right way to parent a young child. Every family has different goals and situations, so what’s best for one family isn’t always best for another. Oster argues that you can discover the best parenting decisions for your family by consulting research and applying strategies from economics to your decision-making process. In her book, she shares advice on making research-based parenting decisions.
Oster, a mother of two and a professor at Brown University, specializes in health economics. Cribsheet is the second book in her ParentData series, which also includes Expecting Better. Both books focus on ways data can inform your parenting decisions. Oster’s findings in Cribsheet are relevant for any parents of young children and soon-to-be parents seeking advice on making research-informed, less stressful parenting decisions.
We’ll begin this guide by explaining why parenting decisions often feel overwhelming. Then, we’ll explore how concepts from economics can improve your parenting decisions. Finally, we’ll present Oster’s research on some of the most important and controversial topics in parenting, from breastfeeding to potty training.
Throughout this guide, we’ll contextualize Oster’s findings by exploring how social and cultural norms and stigmas influence parenting decisions. Furthermore, we’ll supplement Oster’s recommendations with additional actionable advice, such as how to identify trustworthy data and how to reduce your child’s chance of having a peanut allergy.
Oster claims that decisions around parenting are often overwhelming because you must navigate moral judgments, contradictory advice, and confusing data. Parents encounter these challenges when seeking advice from people they know (such as doctors, family, and friends) as well as seeking advice online or in books. In this section, we’ll further explore these three challenges.
(Shortform note: The majority of parents turn to the Internet for information to guide their parenting decisions, and research reveals that much of this information is unreliable. For instance, one study that examined online information on caring for preterm infants found that less than half of websites offered trustworthy advice. Health experts who are concerned about the low quality of online parenting advice urge parents to avoid relying on search engine results and instead rely on these two types of online resources: 1) virtual care visits with your child’s doctor; and 2) websites run by physicians.)
According to Oster, people tend to have strong opinions about which parenting choices make you a good parent, and they harshly judge those who decide differently. Oster surmises that many people attach moral judgments to their opinions to convince themselves that the parenting decisions they made in the past were correct.
(Shortform note: People’s moral judgments about others’ parenting decisions aren’t always based on evidence of those decisions’ actual risks—sometimes, they’re just based on misguided assumptions. For instance, one study found that people harshly judge parents who leave their children unsupervised, even though child abductions are extremely rare. Stories of child abductions receive a disproportionate amount of media coverage, giving people the impression that they’re common. Therefore, people think parents who leave their children unsupervised are neglectful. This judgment can lead to the criminalization of single parents and poor parents, as they’re more likely to leave their children unsupervised out of necessity.)
People’s opinions on parenting aren’t only judgmental: They’re often contradictory, too. Oster claims that there’s no consensus on the best way to parent because what’s best for one family may not be best for another. Because families have different finances, goals, and needs, they make decisions under different constraints. For example, some parents choose to share a bed with their babies because it improves everyone’s sleep. Other parents find it hard to sleep with their baby in the bed, so they put them in a crib.
(Shortform note: The “ideal” parenting strategy may vary even more than Oster implies here, due to wide-ranging cultural norms. Research shows that different cultures and countries have different norms and practices around parenting. For example, whereas most parents in the US don’t allow their toddlers to walk the streets on their own, many parents in Japan send their toddlers by themselves on errands. Some of these families believe this practice is an important way to develop toddlers’ independence.)
One way parents circumvent conflicting and judgmental advice on parenting is by examining research on parenting decisions. However, research on parenting choices is often hard to interpret and challenging to apply to your own life. Let’s explore two reasons why.
First, Oster claims that it’s hard to weigh the benefits and risks of high-stakes decisions: ones that include a risk of death or major injury. When data on a certain parenting decision reveal that an option poses a risk of death or serious injury, we tend to disregard the option’s potential benefits—even if those benefits are significant.
For example, imagine a child is severely allergic to peanuts, and their parent is considering whether to allow the child to share a lunch table with classmates whose lunches may include peanuts. Peanut allergies are potentially fatal: One in every 200 episodes of severe allergic reactions to peanuts results in death. Because peanut exposure has a risk of death, it’s unlikely the parent will spend much time considering the potential benefits of allowing their child to eat with classmates (such as increased social connection).
(Shortform note: In Freakonomics, Steven Levitt and Stephen Dubner explain that this irrationality is rooted in fear: It’s human nature to want to prevent horrifying events, even if those events are extremely unlikely. For this reason, parents also sometimes focus their efforts on the wrong high-stakes decisions. They take extreme measures to protect their children from horrifying yet rare risks instead of protecting them from more common risks. For instance, parents are reluctant to send their children to have a playdate at a house where the parents keep a gun, yet they don’t think twice about sending their children to have a playdate at a house with a pool—even though the latter is statistically more likely to endanger your child.)
Second, Oster argues that research on parenting decisions often fails to show causality: evidence that a certain choice causes a certain outcome. Research that demonstrates causality is helpful because it’s actionable: It provides clear evidence that if you engage in a certain action, it’s likely to have a certain outcome. Unfortunately, research projects that demonstrate causality are rare because they’re harder to design and costly to run.
(Shortform note: Recent technological advances are providing researchers with new ways to produce reliable, actionable scientific evidence when it’s too costly to design research projects that show causality. Innovations in electronic health records systems have allowed researchers to study the results of extremely large data sets. These data sets compile information from myriad sources, compensating for a lack of causality with an abundance of evidence. For instance, research using a large data set about diabetes provided ample evidence about the effectiveness of diabetes drugs—evidence that’s just as reliable, if not more so, than previous, smaller-scale studies that showed causality.)
Oster argues that the best way to overcome the stress of parenting decisions is to apply wisdom from economics to your choices. Economics includes the study of how people make decisions under constraints. Ideas from this field, which we’ll call economic reasoning, improve your parenting decisions in two ways.
First, economic reasoning helps you determine how to make a decision, rather than what to decide. This assists you in making a decision that’s best for your situation, instead of what’s best for other people’s situations.
(Shortform note: Oster’s advice to make a decision that’s best for you, even if it’s not what others have decided, may be easier to follow in some cultures than in others. Cultures exist on a spectrum from having “tight” social norms to having “loose” social norms. If you live in a “tight” culture, such as Germany or Pakistan, people expect you to conform to social norms. In these countries, you may feel less comfortable taking an unconventional parenting approach. By contrast, if you live in a “loose” culture, such as Brazil or New Zealand, it’s more common and acceptable to deviate from social norms.)
Second, economic reasoning helps you better interpret data so you can feel more confident you’ve made an informed decision. Data clarify many of the risks and benefits associated with different parenting decisions, and economic reasoning helps you weigh these risks and benefits in the context of your life. This process can leave you feeling confident that you’re making a thoughtful, well-informed decision.
(Shortform note: You’ll likely feel even more confident in your parenting decisions if you try to counteract your confirmation bias while encountering data. As Dan and Chip Heath explain in Decisive, confirmation bias is our tendency to seek out and favor information that supports our existing beliefs. The Heaths claim that you can counteract this bias by seeking out information that contradicts your beliefs. For instance, imagine you’re deciding whether to allow visitors to see your newborn. You believe that this could make your infant sick by exposing them to germs. To counteract your confirmation bias, seek out research that supports the opposite conclusion: that exposing your newborn to germs increases their immunity to sickness.)
In this section, we’ll explore two economic reasoning concepts and explain how they improve your decision-making.
According to Oster, the economic concept of risk assessment helps you determine whether a parenting strategy is worth its risks. When you conduct a risk assessment, you compare the risks of an option’s outcomes to other risks you regularly, automatically make (such as giving your child solid food even though there’s a risk of choking). This comparison puts the risks of a parenting strategy into perspective: You’ll know how much (or how little) you need to fear a risk based on how much you already fear the existing risks in your life.
For example, imagine you’re considering whether it’s safe to give your infant a vaccine for the rotavirus (a virus that causes diarrhea). Statistics show that 1 in 100,000 infants who receive the rotavirus vaccine experience a serious intestinal obstruction. Let’s compare this risk to a risk most parents regularly take with their infants: bringing them in the car. In 2020, 53 US infants out of a population of 3,735,101 (1.4 in 100,000 infants) died in a car accident. Comparing these two risk statistics reveals that the risk of a serious reaction to the rotavirus vaccine is very low. You know to fear the rotavirus vaccine less than bringing your baby in the car.
(Shortform note: A major benefit of conducting a risk assessment is that it forces you to make a more rational decision, rather than one colored by your emotional state. Research reveals that your emotional state influences to what extent you see an option as beneficial or risky. When you’re experiencing negative emotions, you’re more likely to see an option as high-risk. Taking time to consider data on an option’s risk, as Oster proposes, provides you with objective information that can help counteract the ways your emotions distort risks.)
Furthermore, Oster claims that it’s worthwhile to consider an option’s opportunity cost: what you’d miss out on by choosing that option. This helps you identify an option’s downsides. For instance, imagine you’re deciding whether to breastfeed your baby (which can be inconvenient) or feed them with formula (which can be expensive). Purchasing a year’s worth of baby formula will cost you close to $1,300 more than breastfeeding. Consider what else you could do with $1,300, such as travel.
(Shortform note: While considering opportunity costs helps you identify the downsides of an option, Barry Schwartz argues in The Paradox of Choice that considering opportunity costs can also overwhelm you. Because there’s often an overabundance of options for a single decision, it can be stressful to weigh the opportunity costs for each option. Furthermore, considering opportunity costs may lead you to experience regret: After you make a decision, you may obsess over what you could have done instead. In a later section, we’ll explore how to avoid this overwhelming stress and regret.)
In this section, we’ll examine three goals to work towards any time you make a parenting decision. Throughout this section, we’ll illustrate these goals’ concepts using this one example: deciding whether or not to adopt a furry pet shortly before your child’s birth.
According to Oster, you should base your parenting decisions on actionable data: data that reveal which actions cause which outcomes. Here, we’ll explore why data from randomized trials are more actionable, and therefore more useful, than data from observational studies.
Oster argues that you should base your parenting decisions on data from randomized trials because these studies’ data reveal causality. Randomized trials are a type of experiment in which researchers first randomly sort test subjects into groups. Then, they select one of those groups to experience the variable under study. This process ensures that there are no differences between the groups other than that variable. Therefore, researchers can conclude that any difference in the groups’ outcomes results from the variable studied. This reveals causality. As previously noted, studies that demonstrate causality are more actionable.
(Shortform note: Even research that does show causality may not necessarily be actionable for every family. The identities of research participants don’t always mirror the identities of parents who consult that research. For example, transgender parents are underrepresented in research on parenting, and research on cisgender parents may not necessarily feel actionable to them: A randomized trial on cisgender parents’ milk supply likely won’t include data on how testosterone hormone therapy impacts milk production. In cases like these, transgender parents can still seek information by asking their doctor for help applying studies’ results to their situation or by joining a community support group.)
According to Oster, you should limit how much you base your parenting decisions on data from observational studies because they don’t reveal causality. These types of studies, which make up the majority of research on parenting decisions, compare groups of people without experimenting on them. Observational studies reveal correlations: evidence that two variables are related. Because they don’t involve an experiment, researchers can’t conclude whether outcomes result from parents’ actions or from other differences in their lives. Therefore, these studies don’t provide evidence of causality. This makes them less actionable.
(Shortform note: What if the only data available on the topic you’re researching are from observational studies? In this situation, it’s still better to rely on observational data over anecdotes. When someone you know or someone online shares information about their parenting decision, it’s an anecdote. Observational studies are more likely to provide a balanced viewpoint compared to anecdotal evidence: Whereas information from anecdotes tends to represent only one individual’s perspective, observational studies tend to reflect the outcomes for multiple participants or the average of the outcomes those participants experienced.)
Let’s use an example to illustrate the differences between these two types of studies. Imagine researchers are studying whether young children who live with a furry pet are less likely to later develop a pet allergy. They find 100 pregnant parents who are willing to participate in the study.
Example of a randomized trial: Researchers randomly split these 100 parents into two groups of 50 parents. The researchers give each set of parents in one group a cat and ask the other group to promise they won’t adopt a cat. Because this assignment was random, the only difference between these two groups is whether they have a cat.
Ten years later, the researchers test whether these parents’ children have cat allergies. They find that 10% of the children who grew up with cats are allergic, whereas 20% of the children who didn’t grow up with cats are allergic. Because owning a cat versus not owning a cat was the only difference between these children’s families, these results indicate causality. Exposing your child to a cat causes them to be less allergic to cats later in life. Therefore, the study’s data are actionable.
Example of an observational study: Researchers test the 10-year-olds of 100 parents to see if they’re allergic to cats. They also gather data on which children grew up with a cat. Like the other researchers, these researchers find that children who grew up with cats are less likely to have a cat allergy later in life.
However, these two groups of children could have other differences that explain this outcome. For instance, perhaps families who adopt cats tend to be vegetarians. Do children who grow up with cats have fewer allergies to cats because they grew up with them, or because something about being vegetarian reduces your chance of developing a cat allergy? Therefore, the results of this study are less actionable. They indicate a correlation, not causation.
How to Tell if a Study Is a Reliable, Randomized Trial
If you’re searching for actionable data to inform your parenting decisions, how can you tell if a study is a randomized trial, and what are some indicators that it’s a reliable study?
To identify a randomized trial, look out for language (usually near the study’s introduction) suggesting that the researchers randomly assigned participants to either an experimental group or a control group. This indicates that the trial is an experiment (rather than an observational study) and that the researchers tried to make the variable under study the only difference between the groups they studied.
To determine if a randomized trial is reliable, look for evidence that the researchers tried to prevent bias from influencing the study’s results. These studies are often called “single-blind” or “double-blind” studies. In “single-blind” studies, participants are unaware of whether they’re part of the experimental group or the control group. In “double-blind studies,” both the participants and researchers are unaware of which group is which.
The data you gather from randomized trials should inform your decision, but they shouldn’t determine your decision. According to Oster, you should also consider your and your family’s unique situation: what’s best for your baby, you, and your budget. Results from randomized trials reveal what’s best for the participants in the trial, who may have had different needs, desires, and circumstances than your family.
(Shortform note: To ensure you consider what’s best for your family, you may need to make your decision away from others’ influence. In Predictably Irrational, Dan Ariely claims that when you make a decision in the presence of others, you may feel pressured to make a choice that isn’t in your best interest. This is because it’s human nature to want to maintain others’ image of you. By contrast, when you make a decision privately, you’re more likely to choose what you actually want or need.)
When considering what’s best for you, Oster emphasizes that what’s good for you is often good for your child, too. Therefore, it's important to consider your own desires, needs, and lifestyle when making a parenting decision. Oster claims that, unfortunately, many parents often choose what they believe is best for their child even when this choice would negatively impact them. Deprioritizing their own needs negatively impacts their mental or physical health, which harms them and their children.
(Shortform note: Research supports Oster’s claim that parents sometimes prioritize their children’s needs over their own. For example, many parents are too busy working and spending time with their children to invest in developing their own friendships. Furthermore, some economists argue that economic inequality has led parents to prioritize preparing their children for their future over attending to their own needs as parents.)
Below, we share a series of steps to take when you’ve examined the research on a topic and you’re ready to make an informed decision.
First, list each option’s risks and benefits for your child, you, and your budget. Brainstorm your own risks and benefits in addition to those revealed by the data. For instance, one risk of adopting a furry pet is that your baby is more likely to get bit and develop an infection. On the other hand, adopting a furry pet has benefits: It’ll bring you and your child joy.
(Shortform note: As you consider an option’s risks and benefits for your family, you may also want to also consider how an option affects your community. Some parents make decisions that they believe are best for their children and family, but they fail to consider how their decisions could contribute to social inequality. For instance, some white families perpetuate racial segregation when they choose to send their children to schools that enroll a higher proportion of white students.)
Second, consider how the risks you listed compare to the risks you regularly, automatically take. For example, research reveals that 10 to 20 people (predominantly children) die from animal bites every year in the US, but close to 1,000 US children die each year in car crashes. This comparison reveals that your child’s risk of death from an animal bite is significantly low relative to the risk of having them ride in a car. Next, ask yourself: Are there any ways I could minimize this risk? For instance, you could closely supervise your child and pet any time they’re together.
(Shortform note: As you conduct a risk assessment, resist the temptation to believe you and your family are an exception to the statistics you encounter. In Nudge, Richard Thaler and Cass Sunstein argue that people tend to possess an optimism bias that convinces them they’re less likely to suffer negative outcomes than other people.)
Finally, for each option you’re considering, ask yourself: If I pursued this option, what benefits or opportunities would my family miss out on? For instance, if you don’t get a pet, you’ll never have to find a pet sitter. This might make it possible for your family to travel more often.
(Shortform note: As previously noted, considering opportunity costs can be overwhelming, and after you’ve made a decision, you may look back on the opportunity costs you considered and regret your choice. In The Paradox of Choice, Barry Schwartz claims you can avoid these scenarios by being a satisficer, not a maximizer. Satisficers spend less time on decisions because they’re satisfied with an option that’s good even if it’s not perfect. By contrast, maximizers take time to deeply consider every possibility until they find the best one. They’re more likely than satisficers to regret their decisions.)
Finally, Oster urges you to refrain from harsh self-judgment any time you make a decision that defies conventional wisdom or that other parents are likely to judge as “wrong.” Others’ judgments, which you may internalize as self-judgment, are based on the false idea that there’s only one right way to parent. Instead, reassure yourself that you’ve made an informed, thoughtful decision that’s right for you, your child, and your budget.
(Shortform note: Harsh self-judgments may take the form of an “inner critic.” One psychologist recommends you counteract your inner critic’s judgments using this strategy: Write down what the inner critic “says,” and then write back with a more realistic, generous opinion about yourself. For example, imagine you decide to breastfeed your baby in public, an act that some people judge as inappropriate. Your inner critic may reflect this stigma, telling you it’s indecent to breastfeed in public. Respond in writing by reminding yourself why you decided to do it. For instance: “Breastfeeding in public is legal where I live, and I find it more convenient than seeking out a private space to breastfeed. Besides, I want to help destigmatize public breastfeeding.”)
In this section, we present Oster’s research-based recommendations on several of the most important and controversial issues that crop up during a child’s first three years. Oster reviewed hundreds of studies and claims she based these recommendations on the most trustworthy, actionable research (usually randomized trials). We’ll begin this section with three topics that are relevant to the months following your baby’s birth: childbirth recovery, sleep, and feeding. Then, we’ll cover two topics that relate to supporting your toddler’s independence: potty training and discipline.
(Shortform note: There’s a topic that Oster doesn’t consider in her research that another economist argues is the most important parenting decision: where parents raise their kid(s). Specifically, he cites evidence that children who grow up in neighborhoods with positive role models are more successful than children who don’t. He defines positive role models as people who are smart, are family-oriented, have successful careers, and are committed to their community.)
According to Oster, research reveals that postpartum depression is a serious, common, and treatable condition that you should seek support for as soon as symptoms show up. Symptoms include feeling anxious, having trouble sleeping, having thoughts of self-harm, and deriving less joy from activities you once loved. Either or both parents can experience postpartum depression after their baby’s birth.
Because postpartum depression can make parenting feel harder, it’s best to treat it early. Doctors typically provide you with a survey to screen for depression at your six-week postpartum appointment. If you’re concerned you or your partner have postpartum depression earlier than this, call your doctor to get screened and treated earlier. Treatment typically includes talk therapy, and in more serious cases, your doctor may also recommend you take antidepressants.
(Shortform note: Although Oster focuses on describing and treating signs of postpartum depression after the baby’s birth, recent research shows that early signs of postpartum depression can appear during a person’s pregnancy. For instance, people who experience mood changes and depression during pregnancy are more likely to also experience postpartum depression. This research suggests that you may be able to seek treatment even before your baby is born.)
According to Oster, the period of physical recovery after childbirth varies in length, depending on how much trauma the birth did to your body. If you deliver by cesarean section, you’ll have a longer recovery than if you deliver vaginally. Birth complications, such as vaginal tearing, also prolong your recovery time.
(Shortform note: Recent research reveals that people who experience longer periods of recovery after childbirth can make that time more bearable by engaging in postpartum physical therapy. One randomized trial found that physical therapy reduces post-cesarean delivery pain. Another randomized trial reveals that people who experienced third-degree tearing during delivery felt that pelvic floor therapy improved their quality of life.)
Here, we share Oster’s answers to two common questions about physical recovery after childbirth:
When can I resume having sex? People often say you should wait until six weeks postpartum, but there’s no data to support this. Instead, determine for yourself when or if to resume having sex based on when you want it and when you feel physically ready (with no discomfort or pain).
(Shortform note: Research reveals that couples tend to have less sex after their child is born, but their levels of sexual activity typically return to normal levels after a year. One factor that contributes to this reduction in sex is fatigue: Parenting is tiring, and couples are less likely to engage in sex when they’re tired. Additionally, when you’re busy caring for a child, it’s harder to pursue your urge for sex when it arises, as it’s less common for both parents to be free to spontaneously follow their impulses. According to experts, if you’re looking to carve out more time for sex postpartum, it helps to schedule regular “sex dates.” Ask a family member or friend to watch your child at their home so you and your partner can enjoy some alone time.)
When can I resume exercise? Exercise as soon as you’re physically able to, since it can help reduce symptoms of postpartum depression. Start with less intense exercise, then gradually increase the intensity. If you had a cesarean section, you can typically begin going on walks two weeks postpartum and resume your normal exercise routine after six weeks. If you had a vaginal delivery without tearing, you can exercise as early as one week after childbirth.
(Shortform note: What are the best ways to ease back into an exercise routine after having a baby? Experts recommend beginning with stretching, walking, pelvic floor exercises, and movements that focus on your core, such as lying down on your back and repeatedly lifting and lowering your pelvis off the floor.)
The American Academy of Pediatrics (AAP) recommends that you share a room with your baby for the first six to 12 months postpartum. Contrary to this, Oster cites evidence that sharing a room with your baby has benefits for only the first four months. It’s a good idea to share a room with your baby for the first four months because this is when the risk of SIDS (sudden infant death syndrome) is highest. SIDS is the unexpected death of an otherwise healthy infant. Sharing a room with your baby when their risk of SIDS is highest allows you to closely monitor them. After this, transition them to their own room. Research reveals that babies older than four months sleep better in their own rooms because it’s quieter.
(Shortform note: While Oster claims that room sharing has benefits for only the baby’s first four months of life (the main benefit being the reduced risk of SIDS), one expert claims that room sharing until your baby is six months old makes it easier to breastfeed them. During a baby’s first six months, they need to be breastfed overnight, and this is easier to manage when your baby is in the same room as you).
The AAP also recommends you avoid co-sleeping (sharing a bed with your baby) because it increases the baby’s risk of suffocation as well as their risk of SIDS. Oster shares the counterpoint that according to research, the risks of co-sleeping are low.
(Shortform note: Oster mainly focuses on describing the low risks of co-sleeping, but research reveals that co-sleeping also provides several benefits for parents and infants. First, parents who share a bed with their baby sleep for longer durations because they don’t spend time getting in and out of bed to feed their babies and respond to their cries. Second, babies who share a bed with their parents sleep more lightly, and light sleep is associated with synaptogenesis (the formation of connections among neurons in their brain).)
Furthermore, Oster argues that co-sleeping is safe if you minimize its risks. One way to minimize risks is to avoid drinking and smoking: SIDS deaths are significantly higher when parents drink or smoke before co-sleeping. A second way to minimize risk is to remove the pillows and blankets from your bed, as soft items increase an infant’s risk of SIDS and suffocation.
(Shortform note: Experts note that SIDS has many risk factors, including those that Oster highlights here (parental drinking, parental smoking, and the presence of soft items in bed). According to research, an additional way you can minimize the risks of co-sleeping is to avoid taking sedating medications (such as certain pain relievers and antidepressants) before sharing a bed with your baby. Because these medications deepen your sleep, they reduce your ability to notice and respond to signs that your baby is suffocating or that you should adjust their sleeping position.)
Although infants sleep more deeply on their stomachs, Oster cites evidence that infants who sleep on their stomachs are eight times more likely to die of SIDS compared to infants who sleep on their backs. This is because stomach sleeping is associated with deeper sleep, and deep sleep is linked to an increased risk of SIDS.
(Shortform note: Parents may worry that back-sleeping could increase an infant’s risk of choking if they spit up while sleeping. Fortunately, experts claim that back sleepers are at a lower risk of choking than stomach sleepers. This is because when babies sleep on their stomachs, there’s a risk that anything they spit up will block the opening of their trachea.)
Oster explains that “crying it out” is having your baby sleep in their crib and leaving them alone even if they wake up and begin to cry. Some psychologists claim that this practice reduces infants’ attachment to their parents, and some people claim that parents who let their babies cry it out are cruel.
(Shortform note: Since the publication of Cribsheet in 2019, new research has suggested that these claims are incorrect. A 2020 study found that leaving your baby to cry it out doesn’t impact their attachment or development. Furthermore, this study suggests that leaving your baby to cry it out may help them develop an ability to comfort themselves, causing them to cry for shorter periods of time. Therefore, you could argue that letting your baby cry it out isn’t cruel: It’s a loving way to support their self-control. This research supports Oster’s position in favor of crying it out, which we’ll discuss next.)
Contrary to claims that letting your baby cry it out is cruel and reduces their attachment to you, Oster argues that crying it out benefits both children and parents:
First, children who cried it out as babies experience long-term benefits: higher levels of attachment to their parents and better behavior.
(Shortform note: Here, Oster emphasizes the long-term benefits of letting your baby cry it out, but reaching these benefits may require you to resist your biological instinct to respond to your crying baby. Research shows that the sound of a baby’s cry activates a primitive part of your brain, immediately compelling you to pay attention to it.)
Second, babies who cry it out sleep for longer durations. This is because when they learn that no one responds to their crying, they stop crying and fall back asleep sooner.
Third, parents who have their children cry it out sleep better. This is because they don’t disrupt their sleep to comfort their baby and because their baby eventually cries less. Because these parents sleep better, they also experience higher rates of marital satisfaction and lower rates of depression and stress.
(Shortform note: Whether you’re a baby or an adult, good sleep supports your health, and sleep deprivation harms it. In Why We Sleep, Matthew Walker claims that sleep supports your mental and emotional health: It improves your muscle memory and long-term memory, dulls the sting of painful memories, and boosts your problem-solving skills. In contrast, sleep deprivation reduces your capacity to regulate your attention and emotions and increases your risk of diseases such as diabetes and cancer.)
People sometimes claim that breastmilk is a near-miraculous substance that will raise your baby’s IQ and boost their health. Oster argues that while there’s a correlation between some of these benefits and breastfeeding, there’s only evidence of causation for some of these benefits.
According to research, breastfeeding slightly lowers your baby’s risk of several minor health issues, including rashes, eczema, gastrointestinal issues, and ear infections. However, there’s no evidence that breastfeeding raises your baby’s IQ or reduces their risk of obesity, high blood pressure, respiratory infections, cavities, or SIDS.
Oster cites evidence that breastfeeding can positively or negatively impact your emotional health. Some parents who nurse feel happy, connected to their babies, and powerful. By contrast, some parents who nurse experience frustration, shame, and guilt when they’re unable to breastfeed or they choose not to breastfeed.
Social Stigmas Around Breastfeeding
Research shows that nursing parents face both pressure to breastfeed (often due to its positive effects, as outlined above) and a social stigma against breastfeeding. These conflicting messages may make the decision to breastfeed or not an emotionally fraught experience in itself. Let’s further explore these conflicting messages and consider possible solutions.
On the one hand, parents often feel social pressure to breastfeed, given its many reported health benefits for babies. Therefore, as Oster notes, parents who are unable to breastfeed, or choose not to for other reasons, sometimes feel ashamed. On the other hand, new parents may feel social pressure to not breastfeed: There’s a bias that breastfeeding mothers are less competent in the workplace, and the social stigma against nursing in public discourages some parents from breastfeeding.
To address these social stigmas, one expert claims that public health campaigns that focus on the benefits of breastfeeding should instead focus on promoting social policies that reduce stigma around decisions to breastfeed or not. Specifically, she claims that public health efforts should normalize how challenging it is to breastfeed and advocate for workplace policies that make it easier to breastfeed (such as having a private lactation space).
According to Oster, breastfeeding can positively impact a nursing parent’s physical health. First, there’s strong evidence that breastfeeding significantly reduces your chance of getting breast cancer. Breastfeeding lowers your estrogen (which reduces your cancer risk) and modifies your breast cells (making them less vulnerable to carcinogens).
(Shortform note: If you choose not to breastfeed or you’re unable to, you may worry about missing out on this benefit. Fortunately, there are other ways to reduce your chances of developing breast cancer. The following behaviors are associated with lower risks of breast cancer: staying physically active, maintaining a healthy weight, and limiting alcohol consumption.)
Oster also cites evidence that breastfeeding can cause physical pain. Some people who nurse experience sore breasts and bleeding nipples. You can relieve breast pain by applying any of the following to your chest: cold packs, hot packs, and cold cabbage leaves (which soothe pain and conform to the shape of your breasts). Frenulum surgery can reduce nipple pain. This surgery cuts the baby’s frenulum (where their tongue connects to the floor of their mouth), making it easier for them to latch onto your nipples. If these or other remedies fail to reduce your pain, call your doctor to be evaluated for mastitis (a treatable infection).
(Shortform note: Many of the resources Oster recommends are accessible to most parents: Cold packs, hot packs, and cold cabbage leaves are inexpensive and easy to find. However, some of her recommendations may be prohibitively expensive for some families. Frenulum surgery (which can cost upwards of $350) and mastitis treatment (which can cost over $2,000) may not be covered by a family’s health insurance. Experts are seeking to address some of these gaps in access by offering programs that provide free nursing support.)
It’s common for people to claim that nursing parents should avoid drinking alcohol. According to Oster, research reveals that you don’t need to avoid alcohol entirely. Although your blood alcohol level determines your milk alcohol level, babies are only harmed when you consume more than four drinks prior to breastfeeding. If you want to err on the side of caution by ensuring no alcohol enters your milk, wait two hours per drink before pumping or breastfeeding.
(Shortform note: There’s a possible downside to nursing parents consuming even small amounts of alcohol that Oster doesn’t mention: Doing so disrupts infants’ sleep. One study conducted a trial that observed how well infants slept after consuming alcohol-free breastmilk and compared it to how well they slept after consuming breastmilk with low traces of alcohol. The researchers found that infants who consumed alcohol-containing breastmilk slept less deeply.)
When it’s time to wean your child off breastfeeding and transition them to solid food, two important and controversial topics are 1) pickiness and 2) exposure to peanuts, a top allergen.
Pickiness: According to Oster, research reveals that it’s possible to make your child a less picky eater. If your child doesn’t like a flavor, don’t pressure them to try it or offer them another option. Kids are more likely to refuse food when families engage in these practices. Instead, present your child with a diversity of flavors early on and reintroduce those flavors multiple times. Children tend to like a flavor more once they’ve tasted it on multiple occasions.
(Shortform note: Understanding why your child may be a picky eater in the first place could help you empathize with their fussiness and show patience as you encourage them to try new foods. Some children are picky eaters because they’re “super tasters” who taste bitterness more intensely than other children. Other children are picky eaters because of genetics: They inherit preferences for certain foods over others. These findings show that food pickiness may be rooted in biological factors beyond the child’s control.)
Peanut exposure: People typically claim that you should refrain from exposing your baby to peanuts. Contrary to this, Oster argues that this advice makes children more allergic to allergens rather than less allergic because early peanut exposure reduces children’s risk of becoming allergic.
(Shortform note: How can you safely expose your baby to peanuts? Experts advise that you carve out time to carefully observe how your child reacts to small amounts of peanuts. First, mix two teaspoons of peanut butter or peanut flour into several tablespoons of a food your child already likes (such as yogurt). If they experience a reaction (such as trouble breathing, vomiting, itching, a rash, or a swollen face), take them to an emergency room. If they don’t experience a reaction, you can continue to feed them the rest of the mixture. Continue observing them closely for the next two hours to notice any signs of a reaction. Following this, start your child on a diet in which they eat two grams of peanuts three times a week for at least three years.)
Many parents wonder when to start potty training their toddler. According to Oster, research reveals that most US children complete their potty training when they’re between 21 and 30 months old regardless of how early they start training. If you start potty training early (when a toddler is one and a half), you’ll use fewer diapers—but the entire process of training will take longer (close to 10 months). If you start potty training later (when a toddler is older than two), you’ll use more diapers—but the process will take less time (close to three months).
(Shortform note: Research on global potty-training practices reveals that many parents outside the US toilet train their children earlier than US parents do. This research underscores Oster’s overall claim in her book that there isn’t just one right way to make parenting decisions, and it adds the perspective that your cultural practices shape how you approach potty training. For instance, most toddlers living in rural China are potty-trained before they’re 24 months old, thanks to the help of pants that feature a split seam at the crotch. These pants make it easier for children to use the toilet because they don’t have to take time to remove their pants.)
Parents also wonder what’s the best approach to potty training. Oster argues that there’s no research indicating that parent-driven approaches are any more or less effective than child-driven approaches. Parent-driven approaches such as Oh Crap! Potty Training have you dictate the training timeline, such as when to stop using diapers and when to transition your child to the next phase of training. By contrast, child-driven approaches have the child indicate when they’re ready to start using the toilet and move through these phases. Given these data, Oster claims that the best you can do is strive for consistency: Pick an approach and commit to it.
(Shortform note: Although research provides no evidence that parent-driven approaches work any better or less than child-driven ones, experts claim that which approach you should choose may depend on your child’s personality. For instance, if your child is stubborn, a child-led approach may work best for them. This approach could help prevent your child from resisting your efforts to train them before they’re ready. By contrast, if your child seems eager to please and thrives on praise, a parent-driven approach may help move them through the potty-training process.)
According to research, approaches to disciplining your child are most effective when they 1) don’t involve corporal punishment; and 2) use consistent rewards and consequences. Let’s explore these two ideas further:
No corporal punishment: According to research, there’s no evidence that corporal punishment (such as spanking) improves children’s behavior, and there’s some evidence that it makes their behavior worse.
(Shortform note: Why do parents sometimes resort to corporal punishment, and why does this approach make children’s behavior worse? In No-Drama Discipline, Tina Payne Bryson and Daniel Siegel claim that parents sometimes use corporal punishment when they don’t have another plan for discipline in place. In the absence of a go-to plan, parents base their responses to misbehavior on their current emotions and resort to physical force when they feel angry or frustrated. Bryson and Siegel argue that spanking leads children to misbehave more because it makes them feel threatened. This threat activates the primitive parts of their brain rather than the parts that allow them to calm down and correct their behavior.)
Consistent rewards and consequences: Approaches such as 1-2-3 Magic recognize that when children misbehave, they don’t learn from long discussions about why their misbehavior was bad. Instead, their behavior improves when you reward them or provide them with consequences according to consistent rules.
For example, imagine you’re trying to teach your child to only run when they’re outside. If you ever catch them running, don’t give them a long speech about how running inside is dangerous. Instead, tell them you’ll be taking away five minutes from their outdoor play time (something they love). Any time your child runs indoors, give them this same consequence—even if it feels mean to reduce their outdoor playtime. You can also reward your child any day they refrain from running indoors by adding extra outdoor playtime.
(Shortform note: In No-Drama Discipline, Bryson and Siegel argue that understanding why your child misbehaves prepares you to deliver consistent consequences in a loving, caring way. They suggest that any time your child misbehaves, you should consider what goal or need they were trying to meet. This can help you see things from their perspective, respond more calmly, and implement a consequence that teaches them a lesson without depriving them of their physical or emotional needs.)
In Cribsheet, Oster identifies some of the challenges that complicate the process of making parenting decisions, and she offers advice on how to make better-informed, less stressful decisions. Take some time to apply her ideas to an upcoming parenting decision.
Think about a parenting decision that’s on the horizon for you (whether you’re planning to have a child or currently have a young child). Describe the decision below. (For example, perhaps you’re determining whether to use cloth or disposable diapers.)
Reflect on some of the challenges that complicate the process of making parenting decisions: other parents’ moral judgments, contradictory advice, and the difficulty of interpreting and applying data. Which of these challenges are you currently facing or do you anticipate you’ll face? Describe your encounters with these challenges (or expected encounters) in detail. (For example, other parents might judge your decision to use disposable diapers as environmentally unfriendly.)
Make a plan for how you’ll locate research with actionable data to inform your decision. (For example, you could check out a library book on a relevant topic, reach out to your doctor for recommendations, or browse online for a relevant, randomized trial. If your decision relates to a parenting topic already covered in this guide, describe the findings that are most relevant to your decision.)
List your options for this parenting decision and consider how they’ll each affect your unique situation. Describe each option’s benefits and (known) risks for you, your child, and your budget. Furthermore, describe any ways you can think of to minimize these risks. (For example, babies who wear cloth diapers have a higher risk of diaper rash because cloth diapers don’t absorb moisture as well as disposable diapers do. However, you can minimize the risk of diaper rash by changing your baby’s cloth diaper more frequently.)
Finally, apply economic reasoning to your decision by describing each option’s opportunity cost. Then, reflect on those opportunity costs and everything else you’ve considered so far. Which option are you leaning toward, and why? (For example, choosing cloth diapers could save you $120 to $270, which you could spend on something else—but washing cloth diapers is also time-consuming. You may decide that the time you save using disposable diapers is worth the extra cost of those diapers.)