Here is a (perhaps very lousy) idea that came to my mind some while ago. I might be completely wrong but anyways still like to know what you might think about it.
I've noticed that the beauty ideal among men, as well as women, is more towards young than feminine. It might look as feminine on first glance. But a lot of men in entertainment and media tend to look into this direction:
-face masculine, but more adolescent than clear-cut
-body tall and distinctive muscles
-no beard or only sparse beard growth or stubbles
-no or only sparse body hair growth (also sparse pubic hair)
-voice more tenor than bass
(corresponds to a 16 to 19 year old guy)
for women the equivalent is:
-childlike face
-breasts and pelvis fully developed, but without exagerated fat disposure
-slim and tall
-only sparse pubic hair
(corresponds to a 14 to 18 year old girl)
Please note that
not all beauty ideals tend into this direction, there are many variations, but there is a significant number of it. So how has it come that the beauty ideal of
men and women nowadays corresponds to adolescents who are mature enough for reproduction but not fully grown up yet?
Could it be that the answer is over-aging of society? Usually society picks beauty ideals which it lacks most and which are urgently needed for reproduction. So if a large proportion of the population is underweight from famine and badly sun-taned from a lot of field work, people will pick healthy beauties who are... fat and pale. Take a look on the paintings of Rubens! Or on Renaissance paintings of wealthy merchants/humanists.
The trend towards very young looking beauties started in Japan with the Manga and Anime culture about 30 to 40 years ago, where the over-aging of the population started first. From then it spread to Europe and North America and continues today in Hollywood. And probably this beauty trend won't end until the second half of the 21st century, when the number of seniors in society declines again.
In other cultures however (people who know me know that I'm obsessed with comparing cultures. Sorry can't help it. Someone want to shoot me?

), where youth and old age are still on a normal and traditional level, men are still masculine and women are voluptuous mamas
