In the Sims 2, my sim is a gay guy...?

He has many loves, all of them are guys. So I have this new roommate, a girl, and my sim fell in love with her. I want my sim to impregnate his roommate, but the "Try for baby" option isn't coming up when they're in bed or other places they can have woohoo. Can't a gay guy try for baby? Or is it because they're roommates? They're even engaged! Help me?