If you go back to the beginning of the human race and think about it, you will quickly realize that we were an endangered species. Human females can give birth to only one or two offspring a year, they are pretty much helpless for the last few weeks before delivery; human infants are helpless for their first two years and the survival rate for infants is pretty low in primitive humanity.
Nature's response to this challenge is to give us the ability to get pregnant any time of year (humans don't "go into heat"), and the ability to make ourselves sexually attractive by adornment. It is this latter gift that can cross into fetishism. We can actually learn to be turned on by leather, or red vinyl, or just about anything else.
Nature is pretty much obsessed with sex, when you think about it.