LOL.that is fantastic.
He missed the third cliche. They get raped, they get pregnant, or they get cancer. (But only the good ones get the latter.)
I know that its not quite the same, but the whole "chip in Spike's head" thing could be viewed as a form of castration; not so much directly in a sexual sense, but in the way that vampires feeding replaces / substitutes sexuality in most literature (the works of Anne Rice spring to mind).The difficulty with the analogy of course is the relative ease with which he found a new outlet for his frustrations and then changed completely as a person in order to fit his new circumstances. I'm sure that a genuine eunuch would have much more difficulty coming to terms with their condition.