I never thought about it, until I was told I *had* to think about it because the way I acted, dressed, or moved was 'wrong' and 'people were going to judge me.' Suddenly my life became less about being myself, and mostly an awkward juggling act of 'if I do this like this, will my parents be disappointed in me and I'll be considered a freak? Are people going to hurt me?'
I think absolutely everyone thinks about this stuff, otherwise there wouldn't be such rigid societal expectations as to what would be regarded as 'homo' or 'weird' or 'perverse.' Parents wouldn't feel the compulsion to 'enforce' them on their children from a young age. Boys wear blue, girls wear pink. Girls get dolls, boys play with trucks. Any deviation from this must be weeded out and punished, and if they allow it, what does that mean about THEM as a parent or guardian?
OR even for normal hetero types, how long do you look in the change room before someone thinks you're weird? Do you look at all? If you don't look, do people think you're avoiding it because you're insecure and queer?
Whats the proper positioning in the urinals so no one thinks you're a sicko? (There are even books about this, as there actually IS a correct answer supposedly.)
TL;DR everyone thinks about it, whether openly or not, while they may or may not feel discomfort with it as we do.