They're required never to touch men or small children, too.
They are attracted to it because they are deeply moved by their faith and have decided to dedicate their life to what they see as their Deity.
In fact, your post is incredibly offensive to both Catholics and Homosexuals. You're making an implication that homosexuality and pedophilia are somehow correlated.
I highly doubt anybody becomes a Catholic priest because they don't want to be in a relationship. It would make more sense to do something else and just not be in the relationship.
Why don't you say something like:
Teachers - Think about what type of person would be attracted to a profession that requires them to never touch a child. Teachers have never molested a child before, after all.
Businessmen - Think about what type of person would be attracted to a profession that requires them to wear a suit. They must really hate t-shirts, and this is why they went into the business.
Olympic Athlete - Think about what type of person would be attracted to a profession where they sweat all the time. They must have an unhealthy sweating fetish or something.
Bay12 Forumgoer - Think about what type of person would be attracted to a form of entertainment where fat midgets with beards burn kittens in pits of lava. Of course, of all the ones that are anti-social/sociopathic/whatever else, the vast majority probably still don't act on it.