Last week I played a Baldur's Gate-era CRPG called Arcanum for the first time, and was surprised to find that playing a female character meant a couple of things. First, it meant I would be penalized in Strength and thus inferior at melee. Second, it meant I had only three races to choose from while male characters get like twelve.
Because I'm not interested in the experience of playing a male character, my choices were greatly limited.
One of the most reassuring sights when I play a CRPG these days is when I select the female gender for my character and read the line "women of (generic fantasy realm name) are in every way the equals of their male counterparts". Many games don't seem to even feel the need to point this out anymore. The days of relegating female characters to leather-clad and supporting roles are gone. That makes me happy.
I'm not really a fan of arbitrary sticking points for realism in RPGs in general, but I think a line absolutely needs to be drawn where you start actively excluding people. It doesn't give me any comfort at all whether limiting my character choices makes sense historically or physiologically. It only gives me a very low opinion of whoever is excluding me.