Many find behavioral genetics depressing, but it’s great news for parents and potential parents. If you think that your kids’ future rests in your hands, you’ll probably make many painful “investments”–and feel guilty that you didn’t do more. Once you realize that your kids’ future largely rests in their own hands, you can give yourself a guilt-free break.
…In fact, relaxing is better for the whole family. Riding your kids “for their own good” rarely pays off, and it may hurt how your children feel about you.
If you simply don’t like kids, research has little to say to you. If however you’re interested in kids, but scared of the sacrifices, research has two big lessons. First, parents’ sacrifice is much smaller than it looks, and childless and single is far inferior to married with children. Second, parents’ sacrifice is much larger than it has to be. Twin and adoption research shows that you don’t have to go the extra mile to prepare your kids for the future. Instead of trying to mold your children into perfect adults, you can safely kick back, relax and enjoy your journey together—and seriously consider adding another passenger.
Parents may feel like their pressure, encouragement, money and time are all that stands between their kids and failure. But decades’ worth of twin and adoption research says the opposite: Parents have a lot more room to safely maneuver than they realize, because the long-run effects of parenting on children’s outcomes are much smaller than they look.
Think about everything parents want for their children. The traits most parents hope for show family resemblance: If you’re healthy, smart, happy, educated, rich, righteous or appreciative, the same tends to be true for your parents, siblings and children. Of course, it’s difficult to tell nature from nurture. To disentangle the two, researchers known as behavioral geneticists have focused on two kinds of families: those with twins, and those that adopt. If identical twins show a stronger resemblance than fraternal twins, the reason is probably nature. If adoptees show any resemblance to the families that raised them, the reason is probably nurture.
Parents try to instill healthy habits that last a lifetime. But the two best behavioral genetic studies of life expectancy—one of 6,000 Danish twins born between 1870 and 1900, the other of 9,000 Swedish twins born between 1886 and 1925—found zero effect of upbringing. Twin studies of height, weight and even teeth reach similar conclusions. This doesn’t mean that diet, exercise and tooth-brushing don’t matter—just that parental pressure to eat right, exercise and brush your teeth after meals fails to win children’s hearts and minds.
Parents also strive to turn their children into smart and happy adults, but behavioral geneticists find little or no evidence that their effort pays off. In research including hundreds of twins who were raised apart, identical twins turn out to be much more alike in intelligence and happiness than fraternal twins, but twins raised together are barely more alike than twins raised apart. In fact, pioneering research by University of Minnesota psychologist David Lykken found that twins raised apart were more alike in happiness than twins raised together. Maybe it’s just a fluke, but it suggests that growing up together inspires people to differentiate themselves; if he’s the happy one, I’ll be the malcontent.
Parents use many tactics to influence their kids’ schooling and future income. Some we admire: reading to kids, helping them with homework, praising hard work. Others we resent: fancy tutors, legacy admissions, nepotism. According to the research, however, these tactics barely work. Dartmouth economist Bruce Sacerdote studied about 1,200 families that adopted disadvantaged Korean children. The families spanned a broad range; they only needed incomes 25% above the poverty level to be eligible to adopt. Nevertheless, family income and neighborhood income had zero effect on adoptees’ ultimate success in school and work.
Other aspects of family environment mattered in the Korean adoptee study, but not much. If a mother had one extra year of education, her adoptee typically finished five more weeks of school, and was two percentage points more likely to graduate from college—but didn’t earn more money. If an adoptee was raised with one extra sibling, he typically finished six fewer weeks of school, was three percentage points less likely to graduate from college, and earned 4% less. Studies of Swedish adoptees, and American, Australian and Swedish twins say about the same.
Behavioral geneticists also find that the effect of upbringing on morals is quite superficial. Parents have a strong effect on which religion and political party their kids identify with, but little on their adult behavior or outlook. Some, but not all, twin and adoption studies find that parents have a modest effect on tobacco, alcohol and drug use, juvenile delinquency, and when daughters (but not sons) start having sex. The most meaningful fruit of parenting, however, is simply appreciation—the way your children perceive and remember you. When 1,400 older Swedish twins were asked to describe their parents, identical twins’ answers were only slightly more similar than fraternal twins’, and twins raised together gave much more similar answers than twins raised apart. If you create a loving and harmonious home for your children, they’ll probably remember it for as long as they live.
Critics often attack behavioral genetics with a reductio ad absurdum: “If it doesn’t matter how you raise your kids, why not lock them in a closet?” The answer is that twin and adoption studies measure the effect of parenting styles that people frequently use. Locking kids in closets fortunately isn’t one of them. It’s also important to remember that most studies focus on kids’ long-run outcomes. Parents often change their kids in the short-run, but as kids grow up, their parents’ influence wears off.
Many find behavioral genetics depressing, but it’s great news for parents and potential parents. If you think that your kids’ future rests in your hands, you’ll probably make many painful “investments”—and feel guilty that you didn’t do more. Once you realize that your kids’ future largely rests in their own hands, you can give yourself a guilt-free break.
If you enjoy reading with your children, wonderful. But if you skip the nightly book, you’re not stunting their intelligence, ruining their chances for college or dooming them to a dead-end job. The same goes for the other dilemmas that weigh on parents’ consciences. Watching television, playing sports, eating vegetables, living in the right neighborhood: Your choices have little effect on your kids’ development, so it’s OK to relax. In fact, relaxing is better for the whole family. Riding your kids “for their own good” rarely pays off, and it may hurt how your children feel about you.
Once parents stop overcharging themselves for every child, the next logical step is straight out of Econ 101: Buy more. When you raise your children the easy way, another child is more likely to pass the cost-benefit test. This doesn’t mean you should copy the Duggars with their 19 children; when prices fall, Econ 101 says “Buy more,” not “Buy dozens.” But whatever your priorities, the science of nature and nurture tilts the scales in favor of fertility.
As you weigh your options, don’t forget that the costs of kids are front-loaded, and the benefits are back-loaded. Babies are a lot of work even if you’re easy on yourself. But the older kids get, the more independent they become; eventually, you’ll want them to find time for you. So when weighing whether to have another child, you shouldn’t base your decision on how you feel after a few days—or months—of sleepless nights with a new baby. Focus on the big picture, consider the ideal number of children to have when you’re 30, 40, 60 and 80, and strike a happy medium. Remember: The more kids you have, the more grandkids you can expect. As an old saying goes, “If I had known grandchildren were this much fun I would have had them first.”