Consider your relationship now. You are at the gym and you are both showering together. He is comfortable around you. That is absolutely wonderful. Don't mention the staring at all, not ever, unless it is to the point that other guys are noticing it and making public comments about it.

Sounds like he is not done with puberty. Continue being open. Share a few jokes about penis size or other sexual jokes appropriate to his age that you know that aren't about you or him in any way.

During the summer, I would have a talk with him. First compliment him. Tell him you've noticed he is moving through puberty at a good rate and you haven't noticed any problems. Ask him if he has any questions or issues concerning puberty that he needs to discuss.

At 14 if he is indeed far along in puberty, birth control and safe sex practices need to be addressed. (Some here may not know this, but usually it takes a year from the first full ejaculate for sperm to be present in the semen.)


And whatever you do, don't change how you have always taken showers or talked to him. If he begins to be more modest then you might consider being more modest your self;