I don't think so. I mean, his story's are based on a mythical/medieval time period, and back then it was common for women to not partake in the action (Except for vikings. They wanted all hands on board for their raids and pillages.). This is what makes Eowyn defending her uncle from the Witch King in the Pelennor Fields such a great scene! I don't think Tolkien was intentionally avoiding women.

I think @Logan Flanagan has a great point. The time period that the books were supposed to take place didn't generally have women out fighting in wars. However, that is made up by the types of women Tolkien put into his writing. Arwen, Galadriel, Eowyn, Elwing, Idril... all of them are incredible women!