this is a case of group/frequency dependent selection. as one sex becomes scarce there is an incentive for females to bias their offspring toward that sex since scarcity increases its fitness.

I’ve also heard that after wars, more boy than girl babies are born (i.e., above the 106:100 average) for reasons that aren’t clear, but that some people may suspect are due to the higher average-age of fathers in a postwar society, since younger men are killed in higher numbers– maybe older fathers have a higher Y:X sperm ratio, or something along those lines. In e.g. WWI the British were slaughtered en masse at Ypres and Somme, with many other young British men wounded so badly they couldn’t conceive. So in the 1920′s, the British M:F sex ratio went up as older men began to sire children, though that’s only one theory as to why it increased. (Some other demographer postulated there was also a “bump” in boy baby births after the British were wiped out by the Ghilzais in the Anglo-Afghan War in 1842, though since the Brits managed to get an awful lot of Desis killed in that war too, I’d bet that you may have seen a sudden uptick in boy baby births in affected villages in India, if this process still holds.)

It’s interesting that nature does seem to find ways to keep the M:F balance roughly the same in the midst of various environmental shocks or societal conflicts like wars. I wonder if these various checks and balances still apply in modern industrial society though, since there are factors impacting fertility in general for which I’m not sure there would have been evolutionary pressure. For example, there’s a dioxin-like compound in some plastics that have been popular in industry (I’ll try to find the link), which is deadly to sperm and has been proven to cause dreadful reductions in fertility in areas where pollution is high– the frogs in streams in those areas are infertile and have weird and troublesome gonadal deformities, and there seem to be much higher rates of human male infertility as well. IIRC Europe finally got its act together in the 1990′s and banned the compounds, or at least imposed stringent rules on waste disposal with very harsh penalties for lawbreakers. Whereas, the US Congress still stupidly allows the compounds to be used and is ridiculously lackadaisical in enforcing clean-up and disposal rules. It’s bad enough that these compounds are spilled into groundwater in the US, but many US multinationals also dump this sort of crap in developing countries where they have factories– Malaysia, African countries and I suspect India as well. Worst of all, we may not be seeing the worst effects of these things for another 15-20 years. Maybe Union Carbide in Bhopal wasn’t so exceptional after all.

Cynical my man/woman, deliciously cynical….

Not injecting my personal opinion here, just what the data bore out (I just looked up my old notes to make sure I was not imagining those old teachings). Big difference between American families with several kids and those in impoverished places like India. Those ads promoting 2 child families sound like China, plus one child.

There’s also “the bedroom is the poor man’s opera” reason. Four years of college and that’s one of the few things that stuck, go me! But I’m not completely convinced of the emotional factors being that important. It could also turn out to be that the larger the family, the less time they have to spend around each other because the parents are always working to support the kids. But I might just be too influenced by all those doordarshan ads showing how obscenely happy the families with two kids are

Per the comment “Starving farmers want sons because of cultural and economic prejudice, but their very starving increases the likelihood they have daughter”

This study aside, i recall taking a class in population demographics from an expert in the field during my ivy league years. I always thought, like the conventional wisdom, that the poor people have more children for the sake of having more children to work on the farm, cultural mores, etc. But the data did not bear that out – it came down to emotional factors more than any economic reason. In other words, the bigger your family, the more love there is to go around. When you have little else, such extended affection and support system cannot be underestimated.

bingo. i elucidate the logic here.

Starving farmers want sons because of cultural and economic prejudice, but their very starving increases the likelihood they have daughter

one thing to note, low SES groups in many societies often aver son preference as a form of verbal elite emulation, but on the ground the issues are not so clear. south asia, like most regions (all that i know of), has some hypergamy, where females “marry up.” so, low SES families often have a much better shot of moving up the social ladder through marriage alliances via a daughter than a son. among the masai this has been documented among their “vassal” people. this group avers son-preference, but the reality is that sons have much higher rates of mortality than daughters. a survey of medieval european cemetaries showed many more daughters in aristocratic burial grounds than among the peasantry, where you had a reversed scenario. in other words, cultural biases and economics work at cross-purposes here….

I was under the impression that male babies are more likely to be in trouble from conception to adulthood, so perhaps it’s not so much that a starving mother is more likely to have a girl as a baby girl is more likely to survive a starving mother. I mean, obviously the gender is determined at conception. So, say, girl-zygotes are more likely to get implanted in a starving mother. It’s also possible that starving does something to the conditions in the tubes and canal, so that even with an equal shot of x and y sperm, the x sperm make it upto the egg faster. And then, as above, a starving father might provide more x sperm to begin with.

Which makes me wonder. I’ve been told that during the Bengali Rennaissance there had been an excess birth of girls—which combined with the dowry system to lead to the social problems that inspired Vidyasagar to campaign for widow remarriage and female education. I have no way of verifying that kind of demographic data, but if true, it would also connect with the frequent famines in Bengal in the 18th and 19th century, and the general increase in poverty due to the tax collection. I wonder how that connects with the stories we read about here all the time. Starving farmers want sons because of cultural and economic prejudice, but their very starving increases the likelihood they have daughter. Yikes. Seems like yet another vicious loop in the vicious cycle.

Subhash, sorry to hear about your troubles. How’s Chinese (Mandarin) for career prospects? Conversational spanish is not that difficult, I highly recommend a couple of months backpacking in any Latin American country

Hilarious! I can assure you that there are plenty of others who already have established such a connection and continue to do so. After all, Britney’s transformation from, uh… well, let’s not go there, I think we can all use our imagination here.

BTW, this is totally off-topic but just as a little public service announcement from one Desi to his legions of compatriots in the great halls of Sepia Mutiny:

For your own good, if you have any professional aspirations to work in the US, please budget into your schedule some plans to take courses in conversational and professional Spanish– and get fluent. I’m in the accounting/auditing field, and it’s now gotten to the point that quite a few firms in California/Arizona, as well as in some big cities like New York/Chicago as well as in Florida, won’t hire you without strong Spanish language skills. The same is starting to apply for e.g. law firms, nursing jobs and even retail. If you don’t have Spanish skills, an awful lot of employers these days will take one look at your job application– and toss it into the rubbish pail. Even those who do hire you, will pay you $25,000 a year less than others who can handle Spanish. If you’re still in the Subcontinent, it’s getting to the point that for many fields, I’d suggest you delay applying for a visa until you’ve at least gotten some basic Spanish conversational skills. Eventually, you’ll need to not only be fluent, but also be able to handle official Spanish for formal documents like contracts as well as business negotiations over the phone.

I found this out the hard way myself, as have several of my friends when we’re already struggling to pay off our debts and get a foothold– Spanish fluency translates into jobs and a big boost to your salary for all kinds of jobs, and you just have to have it. You’re tying a straitjacket around your career without it. Moreover, this isn’t just a temporary thing. I was speaking to an old classmate of mine who’s now a lawyer, and apparently, Spanish has official protection and recognition throughout the entire Southwestern USA– including California and Texas– due to the treaty arrangements that concluded the Mexican War that the US fought against Mexico in something like the 1850′s that led to the big transfer of territory from Mexico to USA. (Apparently something similar governs Florida– sorry, I was a B- student in history myself so I only know what my far more knowledgeable friend is able to relate!) So Spanish is here to stay and has a sort of official status throughout a big chunk of the country, and you just have to know it. Take courses, watch Spanish soap operas on the Spanish channels, practice at the deli, whatever you have to do to improve your conversational ability.

I can’t begin to describe how frustrating the job search has been for me here until recently. It’s only after I did some night school courses in conversational Spanish and used some tapes, that things have been perking up. I guess French and German are useful if you want to move to the EU (or to Canada, with French), but for the USA it’s Spanish. So if you alreasy speak, say Marathi, Hindi, English and Telugu, add Spanish to the list if you’re even thinking about North America. It’s pretty much an essential career move.