Update: The Slate piece is not accurately representing the original research:

Lerner’s article is spreading misinformation. What the Guttmacher Institute study shows is not that the educated are having fewer children vis a vis the uneducated, but that there is a growing gap in family planning: the children of the uneducated are increasingly unplanned.

Knocked Up and Knocked Down: Why America’s widening fertility class divide is a problem:

You hear about the “haves” versus the “have-nots,” but not so much about the “have-one-or-nones” versus the “have-a-fews.” This, though, is how you might characterize the stark and growing fertility class divide in the United States. Two new studies bring the contrasting reproductive profiles of rich and poor women into sharp relief. One, from the Guttmacher Institute, shows that the rates of unplanned pregnancies and births among poor women now dwarf the fertility rates of wealthier women, and finds that the gap between the two groups has widened significantly over the past five years. The other, by the Center for Work-Life Policy, documents rates of childlessness among corporate professional women that are higher than the childlessness rates of some European countries experiencing fertility crises.

Childlessness has increased across most demographic groups but is still highest among professionals. Indeed, according to an analysis of census data conducted by the Pew Research Center, about one quarter of all women with bachelor’s degrees and higher in the United States wind up childless. (As Pew notes, for women with higher degrees, that number is actually slightly lower than it was in the early 1990s—but it is still very high.) By comparison, in England, which has one of the highest percentages of women without children in the world, 22 percent of all women are childless. According to the new Center for Work-Life Policy study, 43 percent of the women in their sample of corporate professionals between the ages of 33 and 46 were childless. The rate of childlessness among the Asian American professional women in the study was a staggering 53 percent.

At the same time, the numbers of both unplanned pregnancies and births among poor women have climbed steadily in recent years. About half of all pregnancies in this country are unplanned, with poor women now five times more likely than higher-income women to have an unplanned pregnancy, and six times more likely to have an unplanned birth, according to the Guttmacher Institute’s recent analysis of government data.

It being Slate, the author does not broach what I like to term the “Idiocracy hypothesis”. I invite you to make some observations at a Walmart Supercenter as you stand behind the pregnant 16 year old holding her adorable chubby infant, and then deny the possibility of this outcome. But you don’t need to “go there.” If you have a strong environmental leaning you can still admit that the cultural traits of the middle class may be heritable through acquisition in childhood, while the dysfunctional tendencies of the underclass can also be perpetuated by modeling the behavior of parents and peers. The skewed parental origins of the next generation, and the inferred long term divergence in reproductive output, are issues of some consequence for the broader social order. Systems which shift out of equilibrium may eventually reach a new “stable state,” and one not to our liking.

In any case, here is some General Social Survey data on the mean number of children by age cohort broken down by education for women surveyed after the year 2000. Basically you’re looking at the number of children that women born in the 50s, 60s, and 70s, had by the 2000s.

Solutions? One quick one made by Randall Parker is to allow for easier acceleration of education of the academically gifted. Many school districts seem to discourage skipping grades from what I have seen for practical social reasons. But currently women with professional aspirations have a difficult time having children during their peak fertility years because of the necessary demands on their time of university and graduate or professional school. It is of course true that putting 14 year old teens in classes with 18 year old young adults is going to cause problems, but if a woman can make it out of medical school and into her residency around 22, rather than 26, it is going to be a huge difference in terms of options in their early 30s (beyond the peak fertility years, but not very much).