Well other than that like 90+ percent of all romance authors are female.  Is when it comes to military sci-fi.  Now I'm not saying that female authors can't write good military slant space opera or out and out military sci-fi.  But 'in general' except for female authors that have been in the military they don't seem to do bugs-battleships and blaster-fire as good as the men in my experience.
The Deposed King

This might also be a slant in the writing community.  There are "romance" novels that have next to no romance but they get put in that section of a bookstore or called that simply because of the author being female.  I've had a few female writing friends be encouraged to have a male sounding pen name so that they'll be taken seriously.  Not saying that's all of it but that is likely part of it.

Add to that how women have only recently (technically speaking) been allowed to go into combat zones.  Hard to write what you know when you're not allowed to learn it.  Plus the roughness of the topic makes it difficult I'm sure for some.

As for the whole female MC's sticking with poisonous male characters.  I blame this stupidity that's been growing that glamorizes abusive situations to make book sales (case in point: 50 Shades, Twilight...) and this mentality that's paraded in Hollywood that true love can change anyone into an ideal mate.  It's a load of crap and does nothing but hurt future women.

I shall remove myself from the soap box now.