Funny, this has been a recurring question that pops up once in awhile on the board, and no one seems to really have any true psychological answers (must have to do with the fact that we are not doctors, duh :wink: ) Anyway, my son has done this as well, as well as some other quite odd sexual types of behaviors. I don't know why, and psychiatrists don't know why.
I read here though, that the frontal lobes of the brain are responsible for sexual behavior. So my theory is that if there is any damage to the lobes, or they are not developed fully, one might have some unusual sexual behaviors. Just a laymans theory.
This was a quote from an article, that another board member, SaraPA, posted - and that got me thinking:
"The frontal lobes have been found to play a part in impulse control, judgment, language production, working memory, motor function, <span style="color: #990000">sexual behavior</span>, socialization, and spontaneity. The frontal lobes assist in planning, coordinating, controlling, and executing behavior. People who have damaged frontal lobes may experience problems with these aspects of cognitive function, being at times impulsive; impaired in their ability to plan and execute complex sequences of actions; perhaps persisting with one course of action or pattern of behavior when a change would be appropriate (perseveration)."