Hi Sebastian, interesting question.
My gut sense is that while gender may matter, it would be in a much more varied and complex way than just as pertains to the protagonist or even the author.
On a personal level, while I love such typical 'female' novels/novelists as Austen, Bronte, 'Tess of the D'urbervilles', and 'Anna Karenina', I can respond equally to 'The Great Gatsby', 'Brothers Karamazov', 'The Razor's Edge', or 'The Moveable Feast', to cite just a few. Perhaps it's in part that there's a certain androgynous sensibility at work, in the most abstracted sense (for example, in the lyric poeticism of Gatsby, as opposed to a straight driving linear narrative), though I suspect it's more than this, (and more that they're all great books).
I'll briefly extend to music, which I do for a living. (While this might seem an area beyond gender, scholars have ventured here. I don't do so on that level, but just intuitively.) I admit Beethoven feels very masculine to me (in terms of rhythms, phrase structure, line, harmony, structure) in ways which Chopin, for example, does not. It's nothing to do w/ sexuality. It's about abstracting certain stereotypical associations of gender, neither positive or negative, and using them as vehicles of understanding, like light v dark, hard v. soft, fast v. slow, angular v. curved, external v. internal, etc.
Another favorite novel, 'My Name is Asher Lev', describes a painter who sees two types of artists: those who see the world as geometry and those who see it as a flower. I find it a lovely dichotomy.
Perhaps more to the point, though, even if we acknowledge such broad, potentially gender-linked categories (and it's a big 'if'), people respond both to stuff which resonates w/in them and stuff for which they feel a need or desire. Again, personal example- at a time when I needed to work out hard, I found certain stereotypical 'guy' shows to which I'd never before been attracted made the best background. It's as if they supplied a kind of 'testosterone' which my body needed.
I do believe we're a mix of genders, in all different proportions. Perhaps your female friend may surprise you by accessing her 'masculine' side (in the best sense). Perhaps she'll find something in these 'masculine' voices which refreshes and complements her otherwise female persona. Your friendship may allow her to try these and discover something which she might not have found on her own. In short, nothing ventured, nothing gained.
Good luck!
