But they're all just paraphilias--they seem to have similar causes (when we can identify a cause at all), incidence rates, and forms of expression. The thing that makes certain people's sexuality pathological is that, by coincidence, their fully realized sexual behavior is intrinsically destructive. I feel like I'm not expressing this as cogently as I'm thinking it... simply put, as far as I can tell the only difference between any of these expressions of human sexuality is that some of them have particular destructive results. Clinically, mentally, that righteous killing urge rising in the back of your head notwithstanding, the only thing that seems to distinguish a man who is attracted to men from a man who is attracted to little girls is not the form, but the function of their respective sexualities--that is, the difference isn't in how their attractions work, but in what happens when they act on them.
For example, I have a laundry list of fetishes, and I act on them. Some of them creep most other people out. Some of them creep me out. As a liberal, as a feminist, the fact that my ultimate sexual fantasy basically boils down to a woman with an off switch is a little distressing to me at times. But there are healthy, fulfilling ways to act on all of these kinks, just as with most other alternative sexualities--gay men can fall in love and have families just like anyone else, and I'm blessed with a number of wonderful friends who enjoy having their minds messed with as much as I enjoy messing with them.
But there's no healthy outlet for the ***** they do want them, or at least some do. I have a very dear friend, one of the aforementioned submissive kink-buddies who was molested as a child and still fantasizes about both sides of the experience. What she wants, more than anything else, is a partner she can engage with on equal terms--she doesn't as much fantasize about molesting a child as she does about falling in love with one, having a mature, "consensual" sexual relationship with one. But, well... do I need to explain the problem? I hope not.
***** is the only kink other than bestiality that has no conceivable healthy expression, no responsible-adults-in-the-privacy-of-their-homes aspect to fall back on--and there never will be, because the social taboo is based not on St. Augustine's butthole fixation, but on the cognitive inability of any prospective partner to fully understand or consent to sex. Consider what that means for the patient--what her choices are once she realizes she's attracted to girls about the same age she was. Repress her sexuality--a part of her very identity--for the rest of her life, quietly tamping down her urges and watching literally every other kink and peccadillo slowly emerge into the public eye demanding recognition and respect? Or give in and ruin her life and at least one other person's? It's no wonder so many of the ***** that act on their urges are also stark raving nuts--imagine how screwed up we'd be if we had to live like that.