If you're comfy in them then they're okay to wear if you want to. Personally I think they look good sometimes on either sex, depending on the individual. Looks aside, though, I would think wearing tight pants, especially ones made of non-breathable fabric, might affect a man's sperm count.
Well they don't look particularly comfortable on the man in that picture, but maybe if they were a little bigger they'd be ok. I don't really like tight pants on men or women, except the very skinny who seem to be able to pull it off.