Proper reponse to odd situation...?

The other day I was at the gym and I noticed this weird little dude in the shower staring at my junk, I kept watching him and he was staring for a while. Now I've got no problem with gay guys and I don't care if this dude is gay or not but other people noticed the situation and thought I was staring back at him now there is a rumor floating around that I am also gay. Now normally I don't care what other people think but the problem is that I mainly go to the gym to meet women and now I've got this rumor going around, how do I deal with it? Also the shower dude had a prosthetic arm which kind of creeped me out a little.