In real life, women can shoot pistols (most female gun enthusiasts I know prefer pistols, though some still actively shoot rifles) and drive cars (I don't get why Arma 2 didn't let women drive cars).
As far as combat goes, if I'm not mistaken, the Israeli's have female spec ops units, or something similar.
If not combat, then women can serve as doctors, or intel officers, or something like that.
Also, the Shining Path (Peruvian communist militia if I'm not mistaken) has recruited women to fight for their ideals.
In my personal opinion however, I would find it interesting, but not needed to have female army units/militia.