in the end those are just fetishes that some people have and some dont. i dont think pedophilia can be seen as an illness either. i mean, you dont actually have to **** children to be a pedophile (right?).
Quoting this because while it may appear pedantic this is actually quite important. Earlier on this page somebody asked whether orientation was purely about the act of sex: some say yes most say no. With regard to mental illness, as far as paedophilia is concerned the act itself would imply mental illness because by
definition (no comment here on whether or not I agree with said definition) it constitutes abuse of a child, though this said there exist several special cases in which the court has recognised that the child was a) the aggressor b) precocious c) an active agent who acted meaningfully, making the would-be perpetrator the victim instead, in these cases the "sexual assault of a minor" conviction was overturned.
This is purely due to a feature of how we define children, and the special place children occupy as humans who are not adults: they have protected rights, but said protected rights are not part of a consistent schema. I would have said that their informed consent belongs to their legal guardian who is generally their registered parent, but this only applies so far, since it's obviously illegal to pimp your kids out as that in itself constitutes child abuse (several parents having been arrested and convicted on this charge). Deep down (at least, the only way it really makes sense, which some courts seem to have forgotten about in handing down nonsensical judgements on material that does
not involve live minors, but instead fictional characters) it's because of concerns regarding the behaviours of children and how they would be affected in later life if groomed for sexual acts at a young age. At the same time though compare this to exposure to sexually evocative (or blatantly explicit) material at whatever age, and the dropping median age of onset of sexual activity, and it's not hard to see why in the fine print of legality, even more special subclauses exist regarding the legality and illegality of underaged sex. It's dreadfully cumbersome but the only meaningful change to this status quo that could be effected is if society as a whole changed its attitudes about sexual behaviours and children... and right now that's too controversial a topic to make any real headway on.
Oh man I got sidetracked. The original point: no you don't have to actually
do a sexual act to identify with having the paraphilia. Expressing a desire, or a fantasy, with enough persistence for it to form a part of your identity might be enough to satisfy a psychiatrist. This said, for legal purposes it's only relevant if you've been demonstrated this in some tangible way either in the act, or, depending on jurisdiction, possessing material depicting said acts (with varying degrees of unreasonableness, again depending on jurisdiction).
So lets take that its extreme then. One of your relatives dies and you find out the undertaker's assistant has been having sex with their dead body. Still a preference you can't argue about? Would you argue with their taste then?
There's a fallacy afoot in this. Think about the specific grounds of the objection in your specific example. You would probably say "Hey, stop having sex with my relative's corpse" but you need to realise that you would probably react the same way if you found said undertaker had been mistreating the corpse in any other way. The real issue, in your example, is a breach of trust and the violation of something that you had great attachment to when the person was alive.
Not, as you might initially think, that said violation was a sexual act.