Is this hypothetical paedophile a smart woman or man? Then they keep their mouth shut at work, and go see a therapist.
How do they explain their (behavioural) repulsion to children? Simple - they hate the little sandwich-grabbing yard apes. Can't stand 'em. Say that every friend who has had a kid turns into a "ain't my kid the best ever" drooling idiot and pretty soon they aren't your friend any more.
Much safer and more pragmatic.
Pangloss
This pedophile is a professor. I won't give you where they work, or what department, but to say that they're smart is a definite.
But, to spend your life ostracizing and hurting friend after friend (because trust me, I know people who live like you advise, although I can't say it's for pedophilic reasons, and their lives are miserable), it might be preferable to be as honest and true to oneself as possible, and let the chips fall where they may. regardless, he has the right to deal with it how he sees fit I suppose.