One thing I noticed is genre differences. When I was editing Pagan magazines, most submissions came from women and lots of them were wildly irrelevant. Most of the men were being very thoughtful about theirs, which was good, because in order to keep PanGaia a mixed-gender magazine, we needed things from men and those were in short supply. The exceptions were men who sent things to SageWoman even though it was a women's magazine. I suspect that this illustrates some influences on author confidence: when they're in the majority, as men in SF or women in Paganism, they're more confident and take more risks because they're experiencing an overall high success rate. People in minority or other disadvantaged positions may be less prone to taking risks because it's harder for them to succeed even when factors are favorable.
The thing is, risk-taking can pay off, especially if the worst that happens is someone says no. Men usually don't care about that; many women do. Men also have more disposable income than women, relevant in terms of postage before and affording a computer now. Spray-and-pray occasionally works. The Science Fiction Poetry Association encourages people to submit SF poems to SF magazines that don't accept poetry or poetry magazines that don't accept SF, which has resulted in a few sales. You just have to be prepared for a ton of failure. I note that this parallels the reproductive strategy of males and females: men produce many sperm and invest little in their success, while women produce few eggs and invest much in their success.
Then too, there's socialization. Women are generally trained to be pleasing, which raises the number of them who will read guidelines and try to match a magazine's target. Men are trained to be assertive, which raises the number of them who will do what they want whether it matches the magazine or not.
Editorial bias also factors in. Most editors are men and want stories that make sense and have interest to men. While men and women like to write about some of the same things, there are stories some women like to tell that most men simply won't buy because they don't understand or care about that stuff. There's a brilliant anthology -- I think it's Sisters in Fantasy -- collected on the premise, "Send me the great story that you haven't been able to sell." All the women authors had at least one, and most of them were on topics or in tones that don't appeal to men. This plays into the respective success rate of male and female authors, and their willingness to take risks.
So there's a lot that influences the type of material written, where it goes, how many submissions an author makes, and what gets published.