Evidence for the Trivers-Willard hypothesis: Unhealthy, poorly nourished and low-status mothers are more likely to give birth to daughters because female offspring has a more reliable reproductive success (Song, 2012)

BumblingBeta · 2019-06-10T08:53:53+00:00

Amazing sub

SophisticatedBean · 2019-06-09T23:53:52+00:00

Conversely, male offspring is more of a gamble. Males are more often failures, but a few males acquire high status and hence have more offspring than a female could ever have. This gamble is too risky to take when resources are scarce.

In this study they found evidence for this in birth rate data from China's Great Leap Forward Famine:

The current study examined the long-term trend in sex ratio at birth between 1929 and 1982 using retrospective birth histories of 310 101 Chinese women collected in a large, nationally representative sample survey in 1982. The study identified an abrupt decline in sex ratio at birth between April 1960, over a year after the Great Leap Forward Famine began, and October 1963, approximately 2 years after the famine ended, followed by a compensatory rise between October 1963 and July 1965. These findings support the adaptive sex ratio adjustment hypothesis that mothers in good condition are more likely to give birth to sons, whereas mothers in poor condition are more likely to give birth to daughters.

Related MinuteEarth video: https://www.youtube.com/watch?v=3IaYhG11ckA

Inceliano · 2019-06-24T20:06:46+00:00

Holy shit. I don't think that a person can truly accept the darwinian reality of life without going insane.

crestind · 2019-06-13T02:01:37+00:00

There was a study saying offspring sex in humans is determined by the father's genetics. Which would explain why some men have all boys and others all girls.

BumblingBeta · 2019-06-11T23:41:50+00:00

Interesting study. I also remember reading somewhere that women with higher testosterone are more likely to give birth to sons than daughters.

[deleted] · 2019-08-23T17:54:58+00:00

that is why china and india have excess male as their conditions getting better

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