I had never really thought BDSM at all when I was growing up. Through most of adult life it was only a "kinky" way to occasionally have sex. However, when my wife mentioned to me that she wanted to submit to me totally and be my slave, I knew that it felt right. We talked it over and immediately started. I would imagine that we both were meant to live this way, it seems totally natural to us both.
So after all that is said, I would say that it is something that is innate, then we learn.
Barton.