Study: Men of All Ages Want Women in Their Mid-20s

[Xithras]

330. There's a purely biological reason why women would have less age preference than men.

With human females, increased age correlates directly to increased rates of birth defects and a lower overall fertility rate, with little reproductive upside.

With males the situation is a little different. While the rate of sperm mutations are higher in older men, the very nature of sperm means that only the healthiest are likely to fertilize an egg. This helps to weed out inferior sperm and reduces the odds of birth defects. Females have no similar mechanism to weed out inferior eggs. While the rate of birth defects does increase with the age of the father, the rate is much lower than experienced by women. The primary problem with older men, then, is simply a lower sperm count. The odds of an older male successfully contributing to a pregnancy are lower, but if one does occur, the odds of the child suffering from a disability that would lead to its death or abandonment are low.

Possibly more importantly, human males also have a slight biological advantage as they age. For reasons we don't entirely understand, the length of the telomeres in human sperm tends to increase as the male ages. Those longer telomeres are passed on to the offspring, and longer telomeres appear to be tied very closely to a humans rate of aging and their risk for cancer.

In other words, it may be harder for a women to actually conceive a child with an older man, but if she does so the offspring is likely to live a longer life with less risk of cancer. That means the child will have a longer period of healthy reproduction, which translates to biological success and an evolutionary advantage.

For women, there's little reason to have a biological preference. Younger men have a higher likelihood of causing pregnancy. Older men have a higher likelihood of generating healthier offspring. Both situations are potentially beneficial.