Read an Excerpt

Introduction

Based on persistent headlines about the “mommy wars,” you could conclude that a visit to your local playground or a mom’s group outing might require decking yourself out head to toe in Kevlar. But the reality on the ground is different. There is no war, and we’d like to see that metaphor retired entirely for anything but, well, war.
 
There is, however, a whole lot of bias and judgment. All the time, every second, judging is the background noise of our social interactions. In the parenting arena, that judgment feels—and is—very, very personal. Of all the judgy noise around us, parenting criticism comes through loudly and clearly, a painful signal that elicits defensiveness and anger. Passing judgment on another parent, especially when that judgment is grounded in a “philosophy” of some kind, is a rude and nosy and even hostile thing to do. It’s one reason that some of us rarely do it in our face‑to‑face interactions. But that doesn’t mean we’re not thinking it. And a lot of the time, what we are thinking or another parent is thinking has little to do with what the latest research says.
 
Of course, it’s not a war. It’s human . . . humans raising other humans. Not one thing we do nor one philosophy we follow will guarantee the outcome we intend. We don’t even need science, for once, to tell us that.
 
But science is useful, because the practice of science produces data instead of anecdote—data we can use for evidence-based decision-making as parents. In this book, we look at what science has to say at the various crossroads parents encounter, from vaccines to attachment parenting to circumcision to screen time. We don’t dole out a lot of advice—after all, we don’t know you or your family and can’t say which route would be best for you and your child. But we give you the scientific information you need to map your own path. And here and there, we divulge what we ended up doing, which may not have been terribly scientific at the time.
 
We take on questions like: Should we circumcise our son? Is any sleep-training approach okay? Should I buy conventional or organic food? Is formula all right, because breastfeeding is just not for me? Is home birth ever a safe option? Does too much screen time harm children, and what is “too much” anyway? This book gives you the tools you need to decide, not within the framework of a parenting philosophy but within the framework of interpreting science for your family’s unique situation.
 
Perhaps the most important of these tools is understanding how to decipher the evidence. We don’t tell you what to do, because how you use the evidence depends on your specific circumstances. We work hard to limit or expose bias—yours, ours, theirs. As humans, we commonly overlook gaps in logic and ignore evidence that counters our existing beliefs and expectations. No one, including scientists, is immune to the mistakes in interpretation that all of us make when assessing evidence. As we dig into data, we note the traps to watch out for as you weigh research findings in the context of your personal needs.
 
Mistaking correlation for causation is one of the most common cognitive errors because the human mind seeks patterns and sees relationships in coincidence. That tendency is useful when your friend goes missing at the same time a lion is sighted near your village, and you then are on alert for lions. But it can mislead when the apparent associations are more subtle. Just because organic food purchases have increased at a similar rate as autism diagnoses over the past decade, for example, doesn’t mean they’re related.
 
Another common thinking trap is confirmation bias, which leads us toward information confirming what we already think and turns us away from what contradicts our beliefs. Countering this bias requires playing devil’s advocate with yourself and fighting your natural defensive reaction when evidence goes against a deeply held belief. Be on the lookout: confirmation bias might take hold as you read this book, often taking the form of cherry-picking data that conforms to what you believe. Even if you acknowledge the data, you might be inclined to diminish its relevance or ignore a larger consensus of data. We try to help by representing the entire cherry tree, if you will, in each chapter. We also focus on evidence from research, not anecdotes (even though we share a few from our own lives). As a common saying goes, the plural of “anecdote” is not data.
 
Some kinds of research carry greater weight than others. The gold standard is the randomized controlled trial, in which neither researchers nor patients know who’s receiving what intervention. This study design is intended to erase many of the problems of bias. Other kinds of clinical research include retrospective studies, taking a look back at already collected data and seeing what patterns emerge. But because these investigations weren’t controlled or planned ahead of time, the evidence they yield will be subject to caveats. And then some scientific publications aren’t based on original work at all but instead synthesize existing findings in a subject area. These systematic reviews and meta-analyses are great for getting a perspective of the state of the science, but because the authors select what to search for and include, they can be subject to bias too. The best ones give an assessment of the bias in the studies they evaluate and rate the evidence on a standardized scale. For this reason, we frequently describe the types of studies we’re discussing.
 
Finally, accept the fact that you (and we) probably are overestimating how much you (and we) know and understand. No matter how nice and unassuming you might be or how supersmart you are, you and the rest of us are all subject to superiority bias, known as the Dunning–Kruger effect. In short, it’s our tendency to overrate ourselves while underrating others. Remember how we find ourselves making comparisons to the Joneses and judging each other’s parenting styles, our own most favorably? We’re Dunning–Kruger-ing all over the place when we do that. If most of us are average parents, then most of us are not superior to other parents. What most of us are, though, is hoping to be the best parent we can be in the only situation that matters: for our children. You’re the only parent you need to worry about, and we want this book to help you be the best evidence-based parent you can be.
 
 
We hope this book will save you from the danger of Dunning–Kruger, but we also hope it helps you navigate some of the knottiest parenting questions we face today. Our goal is to place the strongest evidence in front of you, explained in a way you can understand, so that you can accurately decide what’s best for you and your family.
 
A Note on Terminology
 
We are aware of the developmental distinctions between the embryo and the fetus. In some cases, we use both terms when both stages are relevant, but in others, for brevity and to avoid repetition, we default to “fetus” or “fetal.” The word “data” is treated as a plural noun because it represents two or more pieces of information from a study. The term “birth defect” carries obvious negative onnotations, and we have sought to diminish the possibility of adding stigma by instead using the term “congenital anomaly.”