It’s now official. It’s age rather than size that matters. And toy boys are bad for the birth rate.
An analysis of over 10,000 randomly selected Swedish men and women born between 1945 and 1955 has revealed that couples produce most children where the man is older than the woman. Men who partner women six years younger than themselves produce the most offspring (2.2 on average). Women bore the greatest number of children when they chose men four years older than themselves (2.1 on average). By comparison, men who partnered women six years older than themselves only produced 1.8 children on average.
It seems that the cultural jokes about the stereotypical man prefering a ‘younger model’ makes some evolutionary sense. The research authors, Fieder and Huber, speculate that men may evolved a preference for younger women because of their longer fertility span than their older female counterparts. Similarly, women may have evolved being able to give birth more to older men because such men are likely to have greater resources to support the family.
Interestingly the age gap mustn’t be too great. Mothers ten years younger than their partner only produced the average number of children. When the age gap is too great the chances of male fertility problems increases.
Although toy boys are bad for the birth rate, they may no longer be bad for evolution. Historically they were bad for evolution because they would have limited the expansion of the species. However, now that we are in serious danger of overpopulating the planet, it may be more preferable for females to partner with younger males. In addition to the benefit of limiting the expansion of the birth rate, women with younger males may live longer due to increased contentment.
I have often mused on the frequency of older-male relationships versus the older-female kind. The latter do occur but seem rare in comparison though I once read an article suggesting that when an older female takes a younger male under her wing (so to speak) this can be very good for the male concerned who benefits from her knowledge and experience.
I think one has to be cautious, however, when discussing the supposed evolutionary reasons for things. It is all too easy to invent a plausible explanation for an observed effect. Unless there is solid corroborating evidence these “explanations” remain pure speculation.