I was mall shopping with an RJer last week, and he kept remarking about the hot guys, especially in the Apple Store. Certainly a younger crowd there, and not as nerdy as you might assume, some real eye candy.
"Bob, you have great focus!" he said as we left the store, amazed that my eyes weren't checking out all the guys like he was. Well, first, I had a job to do in limited time, whereas he had nothing to buy there. So yeah, I did have focus. Second, as I explained to him, I'm married & monogamous.
And I have this marvelous built-in switch, that automatically takes me from eyes-alert "hunt mode" when I'm single, to "blinders mode" when I'm in an LTR. So crotch watching isn't something I deliberately do at present, unless one presents itself in my direct line of sight. And that includes at the gym, even the locker room.