Yeah actually no though, nature does not determine what people define as attractive or beautiful. This is something determined almost entirely on your upbringing. If you go to pretty much any other country in the world, the reason a man finds someone attractive will be different depending on the country. Beauty truly is in the eye of the beholder in this case. The fact that you like looking at a woman's *** has less to do with nature and speaks more to where and how you were raised.
Actually among the human population certain traits ARE found to be universally "beautiful."
1) Clear skin and eyes
2) Symmetry of features
3) Ratio of waist to hips and waist to chest. In women this will typically be about a 70% ratio of waist to hips and about a 75% ratio of waist to bust (indicating full sexual maturity). This is the true reason a **** looks good-- contrast compared to waist.
There are many physical characteristics beauty that are purely societal, but these are not.
P.S.-- It doesn't matter any way. Whether the imperative is social or biological, there's nothing "creepy" about being attracted to women.
. Parents (typically the mother) force feed their daughters to fatten them up because overweight women are seen as more beautiful. In fact, through history, many cultures have found heavier women (and men) to be more attractive; girth indicated wealth and wealth was obviously someone you wanted to marry. The kinds of anorexic models you see nowadays who could practically play the xylophones on their ribcages would be shunned; no one would even THINK of dating them, lest they be seen in public with someone who looks poor, and can't afford food.
I won't dispute that "normal" bodyframes have been touted over the years in some western cultures (Venus De Milo, David, etc) but different people do in fact find different things attractive.
These things are partially affected by society, but they're also hardwired into our brains. My fiancee (who happens to be bi) and myself have even had discussions over "Why are boobs attractive?" Like, both of us AGREE that we find a nice pair of ******* to be attractive, but cannot understand WHY. Strictly speaking, they're just lumps of fat with a nipple protruding out of them. What it is about ******* specifically that makes them more attractive than love handles, which are also lumps of fat? And why is it that "back boobs" (for lack of a better term) are unattractive? Neither of us can explain -why- we think something is attractive. We just do.