Ben Levi, although the session itself is private, a parent should be able to wait in the waiting area outside the actual office. Any therapist that does not have a waiting room should be nixed for children. Pay attention to your child’s expression and body language when s/he emerges from the session. Don’t get chummy with the therapist, they are there to do a job and that is to help your child. Ask your child how it is going and if they feel they are being helped, if the therapist is a good shiduch for them and if they are making progress. Not every therapist is the right one for the patient, you might have to switch once or twice till you see real progress. Or your child might be lucky and the first one might work. If you get chummy with the therapist and s/he is one of those disgusting abusers then you are helping them by building a relationship with them so you trust them more than your child. Your child will then be afraid to tell you the truth if they are touched inappropriately.
The point is that if your child needs therapy then that is what they need and that is what you must provide for them. If they need a dentist, or an ophthalmologist you provide that as well. The therapy sessions are confidential. Unless your child has a real issue that carries with them into adulthood, marriage and their ability to maintain a relationship and responsibilities without medication then there is no reason that therapy in adolescence must be discussed with anyone at all.