A question: would you assume that your conclusions about books written in English are based on physiological differences in the authors? Surely not--surely you'd say that they're instead social/cultural? That's what I think about any observations about books written by men versus women. I do make those observations--the kinds of books that I read TEND to be written by women. But I'm confident that this is about marketing and about the publishers' expectations about the reading public's expectations. I'm sure that it's also self-selection; as long as I don't dig all that deeply into modern books written by men, then my impression of modern books written by men will be disproportionately influenced by the most popular male-written books, and that will likely more thoroughly reflect social stereotypes.
I was referring to number total of books as a sample rather than male-female diffrences enhanced by socio-cultural determinants. But to answer your question: I base my observations on psychological characteristics of the authors in the first place. Then I look at their social/cultural background but these play a lesser role in my interest. Of course socio-cultural aspects affect the individual but in my opinion the psyche stands above it.
Of course I draw conclusions, but none that would hold water in an academic discourse, which this should be if we are making generalizing observations about the differences between all male and female writers. That's such a huge subject that you need a likewise huge amount of research under your belt (and borrowing a shitload of academic research made by others to support your conclusions... if you can find any, that is). A hundred books is a drop in an ocean in the face of such a topic. Just for fun, I'll also answer @ChickenFreak's question: I think sex does have some influence on how we write, but mostly because of nurture: so many girls are taught from an early age to look at things a certain way, and the same applies to boys, they're taught to behave and think differently etc. etc, so that reflects on the art they produce. In fact, that influences pretty much everything we do, who we are. Here's a simple example to highlight what I mean: if you compare men and women in heavier music circles, men tend to perform in a very aggressive manner (just look at live performances by bands like Slayer, Children of Bodom, Meshuggah etc.) whereas women more often perform in a more "sexual" manner (check out bands like Lacuna Coil, Nightwish, Evanescence, even more extreme examples like Rock Bitch). Of course there are exceptions, like (among men) HIM, Avenged Sevenfold, Type O Negative etc. who do have more more or less conscious sex appeal in their output. Likewise, there are bands where the women aren't as focused on looking pretty and instead have an aggressive stage presence, like the women in Bolt Thrower (the bass player), Arch Enemy, Scatha etc. My point is that, generally speaking, there are some differences in the artistic output between the sexes, but to me it's a tad more difficult to pinpoint them in literature because in music it's so easy: you just look at the performers, what they wear, how they behave onstage (and sometimes offstage) whereas in literature you usually only have the art itself as the material from where to draw your conclusions. Mine are, at the moment, that when e.g. writing action-y bits, men focus more on the little details: e.g. in a sniping scene, what rifle is the MC using? Why that make/model/caliber? How exactly do they set up the rifle, adjust the scope for elevation and windage and at what distance? Also the specifics of the scene, like how the MC seeks out the target on the illuminated reticle 60 of their Zeiss Victory V8 1.8 - 14 x 50 scope, squeezes the creep off the set custom trigger, feels how it breaks cleanly at 1,5lbs, then feels the recoil of the .308 Winchester round, how the top of the target's head explodes and brains and skull bits splatter here and there etc, i.e. the usual "guy stuff." Women, I've noticed, tend to focus more on the emotional side. Yeah, I know, cliche, but honestly, I haven't seen comparable gun or even sword jargon (e.g. what steel a sword is made of, how the MC wipes it down, sharpens the neat flat grind, and reoils it after a practice session, tests how bendy a new blade is, unwraps the grip to check if it the sword is full-tang or a rat tail etc, i.e. stuff I've seen in medieval action-y novels written by men) in action-y novels written by women. They tend to focus more on the story, characters, and, in some cases, outfits (seriously: a couple of authors got a bit carried away with describing what the characters wore). To me, neither is better or worse than the other, but those are some of the differences I've observed from the rather limited scope of my sample. Anyway, all that I'd jot down to nurture, i.e. how boys and girls are taught to think of things, how they're taught to behave etc. essentially from the moment they are born. All that social conditioning carries on throughout their lives and only a minority start to consciously fight that conditioning and even fewer persevere on that uphill battle when e.g. only few girls are actually encouraged to pick up martial arts/combat sports/self-defense, join the military etc. whereas if a boy shows any interest in such things, they usually get far more support from their society than their female counterparts, most of who face judgment, resistance, ridicule, even hostility etc. from their families, friends, peers, and so on as long as they persevere on their chosen path. So it's no surprise far more male authors are well-versed in gun jargon and are actually interested in it (and their mostly male readers are more apt to lap it up and enjoy the details than female readers sans the exceptions). Lately I've consciously searched for action-y novels written by women, especially military sci-fi and medieval hack 'n' slash fantasy to see how women write such material, especially through a strong female protagonist so that I can learn how to better write one myself (since I'm currently writing a strong female soldier in a sci-fi story). I'm aiming for a happy medium between focus on the character, the story, emotions, and the little details like gun and military jargon, the latter of which is abundant in mil sci-fi written by female ex-soldiers (all of whom have so far done an awesome job at it, as far as I can tell), so that's one aspect where male and female authors don't seem to differ. In any case, all those are pretty flimsy conclusions and so far are only at the level of "at the moment things look like this to me." To draw any stronger conclusions, I'd need to put in much more work and likely years of study.
