Yes it does. A unit made up almost entirely of women will suffer heavier casualties than one made entirely of men.
I saw a History Channel program about snipers and they interviewed a surviving Russian female sniper. In the course of the interview, it was revealed that the Soviet female sniper units had about a 75% KIA rate in WWII. No indication was given for male units but 75% in WWII on the Eastern Front seems not too bad imo.