Even if that is true, given how easy it is for a billionaire to have an abortion if they don't want a daughter, and to make sure no one knows about it, I don't think it's proof of anything directly.

I don’t think people are preferentially aborting females to any appreciable degree in the west. Received wisdom is that boys are a pain in the ass to rear. And, anecdotally, most parents are interested in having one of each, not in having one particular sex over the other.

I suspect that received wisdom is highly culturally dependent. The received wisdom in my social circle (western US) is that girls are far more trouble than boys.

What is common in the public at large is not necessarily what is common in the subculture of old money families. Still, I am not necessarily claiming that this is happening, but it certainly seems more plausible than having some psycho-somatic path where wealthier women would give birth to more male offspring. Another even more plausible explanation is that the effect simply does not exist, that the data was not properly collected.

I think a more likely factor would be stopping after the first child if it's what you wanted, and trying for more if you really wanted the other.

But there's so many other confounding factors (e.g. do billionaire men have more testosterone, as either a cause or an effect of their success, do they have children when they are older but the mothers are younger and so on) that it offers no evidence on its own.

> I think a more likely factor would be stopping after the first child if it's what you wanted, and trying for more if you really wanted the other.

In my experience, the primary consideration for most couples is the number of children. Then, if they want more than one, they want one of each. For whatever my personal experience is worth (mostly with middle and upper-middle class Coastal urban people).

Wouldn’t readily available abortion be simply another mechanism by which female mammals could vary the gender of their offspring?

The hypothesis is mechanism-neutral though. ;)

I'd be interested in a citation, first thought which springs to mind is sample size and size of the bias.

Presumably it’s this study: https://www.researchgate.net/profile/Elissa_Cameron/publicat...

It cited 60% male to female billionaire ratio on n of 350.

But, the methodology was to use google and Wikipedia for research so a more honest claim might be “male offspring of billionaires show up in search results more often.”

I suppose that factoid wouldn’t have been paid for by the publisher though.

Thinking more about my own comment, perhaps researchers expecting to find more male offspring while googling find male offspring more often!

Worth bearing in mind that the birth ratio is generally tilted towards boys, about 52.5%

Men with higher testosterone have more sons, maybe billionaires have more testosterone.

There aren't that many billionaires. How many more sons do they have, exactly?