I'm kinda courous about Neoteny and it's correlation in sexuality. This is more of just a thought that I've been thinking of and probability has very little importance. But here's an example: Men both bisexual and homosexual being attracted to features that are neotenous, younger looking in physical traites, like a twink. I personally think I have some featers that are such.
Men usually think I'm plain in person.. then they find out I'm about ten years older than they thought, and suddenly their interest level increases.
Personally, I prefer men around my own age. Preferably no more than 5 years younger, at the youngest.
The primary goal of all life is to procreate. IMO it is in our DNA to try and choose young people who are physically fit with whom to procreate. We know women past menopause can still have sex but they can't get pregnant. Older men also have their sexual problems like prostrate problems and erecrtile dysfunction. So our DNA tells us to find young people with whom we should have sex. If a person LOOKS younger we are fooled to pursue them for sex. So it is advantageous if one can improve their appearance to look younger than they really are. The beauty aids manufacturers are cashing in on this.
Science has all the answers.
Do you mean procreating in by " just having sex to make behbehs (babies)"? Because that goal can be instilled in us without the need for sexual procreation. And if you DO believe that, I would say that homosexuals have a gene-centered view in which survival of our genes is biologically, for a lack of a better word, programmed into our mind without the need to have sex to procreate but to foster others in the continuation of our species.
On the premise of dating younger for sexual procreation is actually a very small contributor. It's more along the lines who is likely to survive the longest and the best, which age, young and old, can help or hinder.