Re: Invalid prayers , if & when you see the opposite gender in the prayer room
I definitely don't think its invalidated. However, I don't know how good your namaz really was if you got distracted during prayer by the opposite sex. I know this sounds counterintuitive and not pcg-ish, but I prefer to pray alone or with just females and with a partition so that I can't see any guys, and no guys can see me. If I have to pray in a small group setting right behind guys, I get uncomfortable. Not so much anymore I guess, but before it used to scare the crap out of me.
I dunno why? I guess I would get distracted by a crush or something? Either way, I couldn't focus, so I would end up not reading with the group and reading alone later on.