This is a good question, one that I think is very difficult to answer.
However I believe that some imbalance inside of a person's brain triggers a sick emotion like this. One may have been treated poorly as a child (sexually molested themselves) been put down all their life. No one that really cared about them. Lonely, miserable, no one that understands them.
I also believe that being bullied as they were growing up can result in wanting control so they lash onto someone that is weaker than their own sense of strength. A lot of it has to do with control issues. They retaliate using control with the weaker sex/children.
A teacher has control to begin with in some ways, so the student that may have this crush on them, is the perfect way to play out the further control they seek..
I think anything to this degree is short of child molestation.The thought of it even going through ones mind means that the tendency of molestation is/has been there all their life. This is a sick pervert.
I do not even believe in sleeping with children of your kids friends, in the situation of a sleep over unless its given permission.
I mean I will have my granddaughter here and her friend and they sleep with me. However if she was having a birthday party lets say, and the party was a sleep over, I would never invite the children into bed with me without the parents permission. It just doesnt seem right.
I would actually like to ask that question, how many would sleep with their friends kids in the same bed.
Research has found that if your child likes the idea of dissecting animals or killing little creepy crawling animals or teasing them to the point where they die, that the tendency for a serial killer is there.
So maybe they should research the similarities between sex offenders, and deal with the problem.
I also do believe that one can be born this way, but do not act on it, or understand that feeling until given a situation that will make this come into play.
Its like being gay, we dont wake up one day and decide we want the same sex relationship, at one point we realize we have felt different and act on it. It just make take a situation to come out of the closet.