If you want to see a guy's penis are you gay?

You are gay if you are sexually and/or romantically attracted to the same sex. That is the only way you can know.

You could want to see a guy's penis for many reasons, curiOSity, envy, jealousy, anxiety that it might be better than yours, lots of reasons. That doesn't make you gay.
you are probably gay for being on this web site butholes.