If I had a son he would not be inspecting other people's dicks, unless he turned out to be gay of course. Why should we be so paranoid about our genitalia? There's no reason to worry over a natural penis, it's just a dick.
There hasn't been a boy in the history of communal showers that hasn't looked. If for no other reason than to make sure they are falling in the normal range...
It has absolutely nothing to do with homosexual feelings.