I also realize that it would be idiotic to assume that something like a rubber fetish or love of high heels could be genetic.
How so? When broken down to the most basic level, homosexuality is nothing more than a fetish for having sex with members of the same sex (just as heterosexuality is the opposite and asexuality seems to be the lack of either), and since there's now a growing view that homosexuality is the result of genetics, what's stopping one person's desire to be spanked from from being the same?