Until recently it was thought thatmenopause, a period of a woman’s life in which she stops producing eggs and which is almost exclusive to human beings, was the result of an evolutionary strategy aimed atprevent women from reproducing after a certain ageso that, in this way,act as grandmothers and take care of their grandchildren(the so-called “grandmother effect”). But a team of biologists from McMaster University, led by Rama Singh, argue that this theory makes no sense from an evolutionary point of view and claims to have found an alternative: thatthe reason for menopause is that men routinely choose young women as a partner. And that, therefore, in the face of the predominant lack of female reproduction from 45-55 years of age, biology has been altered so that at that age the female fertile period ends.
To reach this conclusion, the researchers developed a computational simulation model in order to verify whether the preferences of males would cause the accumulation of mutations that affect the fertility of females at maturity, as explained inPLOS Computational Biology. The simulations revealed thatwhen model males had no age-related preferences, female fertility was maintained throughout life. But when they preferred young females, menopause appeared. The menopause, therefore, would not be a change that increased the survival of the species, but simply a biological recognition that female fertility was useless after a certain age.
According to Singh, if women had historically selected young men as partners, the situation would be the opposite: men would become infertile when they turned fifty.
