Status, Stress and Sex Ratios opens with a few factoids:
The presidents of the United States have had, collectively, almost half again as many sons as daughters (148 to 102 if I’ve counted correctly). Far more strikingly — because the sample size is so much larger — the people listed in Who’s Who have, collectively, about 15% more sons than daughters.
Humans have been polygynous through most of their (pre)history. Almost all women have children, and there’s relatively little variation in the number of children they have. On the other hand, many men father no children (low-status men often have no access to women), while other men father dozens (high-status men can have access to dozens or even hundreds of women). Apparently, high-status women unconciously produce more sons to take advantage of this:
One suggestion from the biologists — and one that makes very good sense to an economist — is that a pregnant woman’s body, in deciding how much to invest in nourishing the embryo, takes account of the parents’ status and the embryos’ sex. High status mothers give more nourishment to male embryos; low status mothers give more nourishment to female embryos; better nourished embryos are more likely to be born alive.How can a process as involuntary as nourishing an embryo respond to conscious information like the status of the father? Well, how can a process as involuntary as sweating with fear respond to conscious information like the approach of a tiger? Clearly this kind of thing happens all the time. More fundamentally, decisions like how much to nourish your embryo are among the most important economic problems the body ever faces. Is it really plausible that the body would simply throw away highly relevant information when it’s making a decision like that?