I do think it has to do with population control. Casual, sterile sex during the most fertile years of life is encouraged, homosexuality is encouraged, jobs that can support a family without spending many years in school are few and far between.
Also, looking at it from the lense of population control, it would make sense to demonize older man/younger woman relationships but not older woman/ younger man relationships.
A 35 year old man with a 15 year old girl can still produce many children. On the other hand, a 35 year old woman cannot produce anymore children with a 15 year old young man than she could with a man her age, so it doesn't matter. She will still produce 1 or 2 children with a 15 year old just like she would a 35 year old.