It may be just me, but going to a class only for the female presence seems like a waste.
You have the chance to choose something you like aside from your faculty courses either for curiosity or hobby purposes and to seriously learn about it.
Besides there are two other possibilities: you choose something complementary to your faculty, in order to specialize a bit and have an edge on other graduates, or choose something diametrically opposite, to see more of the variety and to generally have a more open mind.
All of these would be extremely tempting for me.
Imho the female factor should be secondary at best.
Edit: "Jack of all trades, master of none,
Often times better than a master of one"