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.And:
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.And, in summary:
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.