This actually happened in the movie...well, the first two lines of dialogue anyway...

It was really odd...even the Ilsa stares at Renault in a funny way...I know in my History class we all just kinda stared at each other when he said that...this movie was made in the late 30's or something, and they made a gay joke?

But, hey, maybe they didn't do it on purpose and a guy saying that if he was a woman he'd be in love with another man was a totally normal, non-gay, thing to say during that time and now as teens in the year 2011 we just happened to take it that way...!

....Or maybe Renault honestly wants to get in Rick's pants. Heaven knows he's already tapped everything else in Casablanca already.