Sunday, November 18, 2007

More Stress Fewer Boys

A boy or a girl? That is usually the first question asked when a woman gives birth. Remarkably, the answer varies with where the mother lives. In rich countries the chances of its being a boy are about 5% higher than in poor ones. Equally remarkably, that figure has been falling recently. Several theories have been put forward to explain these observations. Some argue that smoking plays a role, others that diet may be important. Neither of these ideas has been supported by evidence from large studies. But new research points to a different factor: stress.

Dr Obel found that the more stressed a mother had been, the less chance she had of having given birth to a boy. Only 47% of children born to women in the top quartile of stress were males. That compared with 52% for women in the bottom quartile. Dr Obel suspects the immediate cause is that male pregnancies are more likely to miscarry in response to stress than female pregnancies are, especially during the first three months. However, that is difficult to prove.
That is amazing to me that stress can reduce the percentage of boys born by 5%.

Ladies, please, easy on the stress. The future of the male sex depends on it.

via The Economist


Audacious Epigone said...

No no no, FK, more stress for women. A high male-female ratio isn't good for guys, a low one is. Supply and demand...

Seriously, I wonder if stress inhibits the development of adrenal production and phallic development.

Fat Knowledge said...


Good point, we don't want America to start looking like China. :)

I don't know what the process is. I do know that male sperm swim faster than female sperm, so that there are more male conceptions to female conceptions. But then it is downhill for guys as they have a higher death rate from there on out. I know that testosterone decreases the impact of the immune system, but I don't know if that would apply to these fetuses or not.

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