I'm female, and if I see an attractive guy... I might imagine for a second how he would look naked... might even end up improving on the 'real thing' for all I know. Then it's back to work.
If I see a woman that I find attractive... you bet I'll imagine her naked. I can't stop it... my mind is curious...
Between the two genders... women make it much more difficult to keep your imagination from kicking in... by nature some are designed to be almost works of art, then so many of them have perfected the art of movement, their voices can be sensual (even when they don't mean to be), and then the clothes they wear are designed to accent their natural beauty. Then couple that with sex drive... and you'll end up with very sexual fantasies --- fleeting as they may be.
There's nothing wrong with having sexual thoughts. Sexuality doesn't necessarily equal disrespect. Sex merely is... the emotional implications are highly dependent on the individuals involved --- not the act itself... or.... one gender.
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen