Just because he is married with a child doesn't mean he wont continue to hurt other children, or sadly enough even his own. I don't want to pass judgment but in this case I would say you have a responsibility to the children in the congregation to report this. The elders won't do anything if you tell them, they will sweep it under the carpet, that is assuming they don't already know and are just keeping quite. Perhaps you can let parents in the congregation know anonymously, no matter how you do please make sure people know.
CS