Many people say that having children gives you a much better sense of the power of genes in shaping behavior. At least in the abstract sense that is not true in my case. I accept the “conventional wisdom” from behavior genetics that “shared environment” (colloquially, parental input) is relatively marginal in effecting much long term change within reason (i.e., if you don’t beat your kid over the head with a baseball bat and such you don’t have much influence).
To review, on many bio-behavioral traits the different choices parents make seem to account for on the order of ~10 percent of the differences you see in the world out there amongst their (biological) offspring. Of the remainder of the variation about half of it is attributable to variation in genes, and the other half to unaccounted for non-shared environment. In The Nurture Assumption Judith Rich Harris proposes that that last effect can be reduced down to social environment or peer groups. Her line of argument is such that parents are important because of the genes they contribute, and, the environmental milieus which they select for their offspring.
On one level I …