No, it's not. If you had seen the inside of a gym in the past decade, you'd know that women can develop pretty much the same strength that men can. They just won't develop the same muscle size.
The
SOLE reason more women (who want to train or lose weight) don't hit the weight room as hard as men do is because they've been taught (wrongly) that lifting weights will make them "ugly" and "bulky" (not true, unless they down supplements like crazy and dehydrate themselves dangerously).
So, in a universe where civilization is under threats from ogres, orcs, trolls, and all sorts of vile nasties, and where every sword-arm is required to protect the cities and towns, you're telling me that a girl who chooses the path of the soldier, who's going to train from the age of 12, 13, 15 tops to be apt at fighting, wearing armor, etc. is going to be less strong than her male counterparts. That's simply not gonna be the case.
Here are a few exemples to educate yourself:
http://www.youtube.com/watch?v=IyzLpODqxrE
http://www.youtube.com/watch?v=StkKrqvD7l
http://www.youtube.com/watch?v=rqDEeIv8Rd4
(that 13 year-old benching close to 200 lbs is crazy. I'm thirty-one, been training for close to six years, and I plateau'd at maybe 250.)