When I found out that my youngest son had been molested by an older neighbor's boy, I asked him if it ever caused him to be gay. He said NO. I believe him. I know it can happen, though. Some become male prostitutes. We need to pray for these kids.
It can also lead to addictions later in life, be it alcohol, sex/porn, drugs etc when the victim doesn't get help for the initial abuse. Prayers that your son has recovered from this as best as one can.