The basic idea is this: Whenever parents have genetic traits they can pass on to their children that are more valuable for boys than for girls, then they have more sons than daughters. Conversely, whenever parents have genetic traits they can pass on to their children that are more valuable for girls than for boys, then they have more daughters than sons. Physical attractiveness — being beautiful — is good for both boys and girls, but it’s much more advantageous for girls. Physical attractiveness of a woman is one of the most important considerations for men when they select both long-term and short-term mates, but a man’s physical attractiveness is important for women only when she’s looking for short-term mates. Women like to have affairs with good-looking men, but they don’t necessarily want to marry them, unless of course they are also rich and powerful.
That’s from this worthwhile interview with Satoshi Kanazawa, author of Why Beautiful People Have More Daughters: From Dating, Shopping, and Praying to Going to War and Becoming a Billionaire– Two Evolutionary Psychologists Explain Why We Do What We Do.
(hat tip: Ryan Holiday)
I recently discovered Kanazawa via German Joys, aka Andrew Hammel. He has a great writeup of this and other Kanazawa papers in this post. However, it seems that there is criticism of Kanazwa’s statistical rigor and from my limited Cognitive Science background know the dangers of Just-So stories in Evolutionary accounts.
Still, Kanazawa has no fear in slaying sacred cows. (Andew has a long list in his post.) There’s a certain self-referential comedy in a college professor writing a paper on Teaching May Be Hazardous To Your Marriage.
Did you know that rich families tend to have more sons? Why? Because young men with money tend to be more sexually prolific than young women with money. Poor families tend to have more daughters because having a daughter (often an economic asset) helps them move up in status.
what do George W Bush, John Kerry, Bill Clinton, Dick Cheney, and Barack Obama have in common? Answer: loads of daughters!
I’ve read that at conception, there are up to 20% more males than females (most miscarriages are males). This is because the Y chromosome is lighter than the X chromosome, so “Y” sperm are just a bit faster. However, what the Ys gain in speed they lose in genetic viability, especially if Mom carries a deleterious gene.
The Y chromosome is also responsible for the scourge of hairy pinnae.
If the editorial review from Publishers Weekly of Kanazawa’s is correct, and he actually wrote “10,000-year-old impulses to find the right mate and produce healthy offspring control nearly every aspect of our existence”, I wouldn’t bother to read the book.
I would say that anyone who believes those evolutionary impulses are only 10,000 years old has the all the statistical rigor of a believer in Biblical inerrancy and creationism.
@ Ryan Holiday:
“Poor families tend to have more daughters because having a daughter (often an economic asset) helps them move up in status.”
Most extraordinary view of poverty! In many patriarchal cultures in poor countries, including India, the custom is that marrying a daughter off costs a lot of money (in the form of dowry) and keeping her unmarried to contribute economically is a stigma. Poor people do care an awful lot about social stigma.
Sons in the same cultures bring dowry in, stay with parents (unlike the daughter who goes to live with or serve the in-laws)and inherit the assets keeping the wealth in the family.
So the argument – if at all there is one – is the other way round. Families do not want daughters because they are seen as harbingers of poverty.
@ Ben: This post first made me laugh, then call my father (a father of girls, who did not diminish his wealth, because they are well-educated professionals and found their own husbands where applicable), then wonder how this might pan out in an illegal abortion clinic in India:
“Oh, doctor, so you think it is a girl?”
“Yes.”
“And that means I am beautiful?”
“Well, yes, so evolutionary theorists would say”.
“Ok, thanks and all for the compliment. Now can you hurry up and complete the abortion?”
End of.
Several million female foetuses and infants are killed every year in India and other countries around the world. If only this argument of vanity could help stem some of those!
I wrote the same thing on your site:
It’s not a view of poverty. It is a fact. Poor families have on average more daughters while richer families have more boys. Not because it helps them economically but evolutionarily. If you’re rich and you have a boy, he will on average, father more children than if you’re poor and you have a boy. Conversely, if you’re poor and have a daughter she will have more children than if you were rich. It’s not an argument. It is a statistical fact.
Ryan:
Thanks. I asked the same thing on my blog too. I am happy to confess my ignorance of these statistics and with that backdrop, framed your argument in a societal context that I am familiar with.
It would be immensely helpful for me to understand your perspective if you could share the sources of these statistics.
Thanks.
Sperm Wars by Robin Baker or the above mentioned book.
I agree with you. It’s much more advantageous for girls to be beautiful than for boys. But I believe that people cannot give birth to a baby of the sex they want. That’s why it’s just a lottery.
If you’re an avid PS3 gamer, then you know the importance of saving your progress for future game play.
Pls, help me!