As a female American baby boomer, I have only seen what the media offers as what "war" is (both the documentary stuff on Viet Nam and the Gulf War as they happened, the news reels and documentaries on WWII, and the fiction films from Hollywood).

I wouldn't know, but I would assume that maybe the fact that there is a common theme is because there is a common experience of war.

Ask a few veterans for *their* stories if you want to test the theory.