Friday, November 19, 2004


Sperm's solution to promiscuity

Nature is fighting back in response to female promiscuity by producing a biological 'sperm' chastity belt, say US scientists.

Semen becomes more sticky to act as a plug, thereby preventing sperm from competitors impregnating females who sleep around, they found....

The researchers examined the semen of 12 different species of primates.

In species where the females were most promiscuous, the males had developed several strategies to ensure they would be the male most likely to father any offspring and pass on their genes.

As well as having larger testicles and producing more sperm, the semen was more sticky.
Chimpanzees, for example, which are a promiscuous species, had more advanced evolution of a gene controlling the stickiness of semen than gorillas, which tend to be monogamous and stay faithful to their partner for life.

Humans were midway between, suggesting that while women are nothing like as promiscuous as chimps, neither are they as faithful as gorillas....