Supernatural (tv series) - Character Analysis

So, I noticed in the fanfictions that there are a lot of M/M romance stories, and I got to thinking about why that might be. There are a lot of readers for M/M stories, sure, but is that the only reason? When I considered which M/F pairs I'd make from these characters...it became obvious that there are not a lot of female characters to work with. And if you take character development into account, the difference is even more obvious. The fan-favorites are simply more likely to be men than women.

To check if this theory has merit, I am making an analysis of each character's development in the series.

We're looking for back story, character traits, relationships, and character arcs.
• +1 point for a fact
• +3 points for a characteristic or trait
• +5 points for a relationship formed or changed
You only get points the first time a fact/etc comes up, not each time.

This will be chock-full of spoilers, so the reasons for the points start off collapsed/closed.