These kinds of posts are better when the OP has brought some research to the table.

This article is written entirely from a male perspective. As a 17 year old girl I find inflammatory the way the female view point is completely absent. I think you will find that the vast majority of young women my age, myself included, are not attracted to "older" men. I also don't understand why you keep referring to "evolution". In no way would it be biologically advantageous for someone my age to procraete with an old man. You seem to forget that although men may generally remain fertile for longer than women, male fertility still declines with age. This is evident in the fact that their are increased health risks for offspring of older fathers as well as older mothers. The desirability of older men to young women only makes sense within a culture where stature and power are desirable attributes, and are more commonly held by older males. In a purely biological sense, it would make sense for young women to have children with young men who are most fertile and capable of handling the physical demands of raising a child. As the treatment of the sexes becomes more equal women have morer power and autonomy. They no longer need to rely on male counterparts to determine their position in society. Relationships are increasingly built on companionship, respect, and shared interests which are more commonly found in similar age partnerships.

who benefits from this norm [older women]

Tsk, tsk. The norms were set up by a culture of powerful men, in order to benefit powerful men. Who benefits from the changing norm? Anyone who isn't a powerful man.

Did you ever watch that film A Beautiful Mind? Spreading out romantic advances is the pareto optimum. If nobody is sleeping with the older women, then also nobody is sleeping with the non-powerful men. Changes in sexual patterns can be thought of as victory for the average human.

And it's certainly not all sunshine and roses for the young women. Power imbalances in relationships are a risk factor for things like marital rape, controlling behavior, and general bad stuff. Oh and there's the whole "treated like property for large chunks of history" part. And as we go a bit younger, do you know what a fistula is? Yeah, just... I'm really glad the sexual norms have changed.

The best solution I’ve heard started by looking at who benefits from this norm [older women] and wondering whether they could have contributed to it.

Young men benefit from the decreased competition in the mating market.

Another, less plausible, suggestion I’ve heard is that it’s to do with mental capacity. I find this unconvincing because we have few objections to a high-status man dating a beautiful but low-intellect woman.

The objections never seemed all that few to me. The negative connotations of the term "trophy wife" are pretty well-established, IMO.

Security changed. Women are no longer forced to seek protection from powerful males in order to avoid sexual assault and the death of their children.

Puberty occurs much earlier in modern societies. Recently postpubescent girls and boys are children, and most people are turned off by the personalities of children (which of course makes evolutionary sense, as well as cultural sense in most societies). The age group you're thinking of is closer to 18 than to 15.

We have relatively gender-egalitarian norms now. In societies when older men are encouraged to date young women (and/or young men) the relationship is very asymmetric. We like having power-equal relationships, because we think it more moral, becaus... (read more)

I think we should look at this from a "Farmers and Foragers" perspective, as Robin Hanson often does. Foragers don't tolerate non-egalitarian relationships, and a young, vulnerable woman and an older, more-settled man have a wide gap in power. Farmers accepted marriages between young women and older men because they have more tolerance for power differences and less expectation of equality. More recently, we have switched back from farmer-style culture to forager culture, and these old-man/young-woman relationships are less tolerated.

I also thin... (read more)

Why don’t men go for younger women?

What? They do. (My father is eight years older than my mother.) And maybe it'd be better if they didn't.

The best solution I’ve heard started by looking at who benefits from this norm [older women] and wondering whether they could have contributed to it.

Indeed, I've often witnessed women apparently suddenly lose all interest in a man as soon as they found out he was younger than them, whereas I've never seen the reverse (except in an “I don't think she would ever get with me since she found out I'm this young, so I... (read more)