I was asked recently how I could be a Christian and also be into BDSM. How to reconcile the two. (I am sure everyone in this room has had the same discussion at some point.)
My answer was that as long as it was monogamous, I didn't have a problem with the two at once. And pointed out the bible teachings discussed above.
Our current gender roles in mainstream society where men and women are supposedly exactly the same in every single possible way, has only been around for a generation or two. It wasn't that long ago that men really were the head of their households.
It doesn't mean that men are getting off light here either. One of my friend's fifteen year old son started spouting off while I was visiting about how great it would be once he had a family and he could be in charge and do what he wanted. So I started discussing with him all of the responsibilities that came with that role. He had to demonstrate how to be a good Christian, teach his sons to become good men, his daughters how men should treat them, and be a loving and supportive husband. All of a sudden, it wasn't all that appealing anymore.
I think when we remove all of the messages that "society" is telling us, many fall back into these traditional roles. Certainly one of (not the biggest, but one of) the things that drew me to D/s is the fact that you can find such a relationship.
It definitely appears that there are more Dom/sub relationships than there are Domme/sub relationships. I would expect that this is due to our natural gender roles that we aren't supposed to be acknowledging according to mainstream society.
(Disclaimer - in no way am I trying to imply that Dommes and male subs are unnatural, or illigitimate, or anything else bad. I am just making gross generalizations.)