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May 22, 2003

And she begat daughters....

This article in the Economist reports the preferential skewing toward females among malnourished Ethiopian women at birth. The two reasons given are that male fetuses drain more resources than female ones and so might be aborted at greater rates while additionally daughters are a more likely a possibility to pass on genes in hard times [1]. The dynamism inherent in pregnancy can be further illustrated by this article that elaborates on the effects of birth-order, immune reaction by women to male fetuses and possible ramifications for homosexuality and other phenotypes.

On a cultural note, though most societies seem to evince son preference, a recent study (which I can't find via google) indicated that medieval european peasants tended to kill & neglect sons, while the gentry exhibited the male preference that we expect (they surveyed headstones at graves in the cases of infants). The modern tendency in cultures like India and China to be male-skewed might be an instance of elite emulation facilitated by mass media. In contrast parts of Europe and Japan are now shifting back toward daughter preference (in times of plenty).

Finally, I would like to add an interesting personal note. My mother is one daughter with six siblings, all of them male. My father is one of four boys and two girls. At least for the past 200 years I know my family has been of moderately elite status on both sides (though no longer in the West of course!).

[1] David Sloan Wilson uses the balanced sex ratio as evidence for group level selection-he argues that individual interests favor having sons, while group selection favors daughters, and the parity indicates an cancelling of these forces.

Posted by razib at 02:03 PM