It can't be denied that any text bears an imprint of the personality of the person who wrote it. Thematically, it bears an imprint of your interests. Stylistically, the way you write is a very personal way of expressing itself. It might be something you have honed for years. However, I do find that people can get too carried away with this line of argument. To persistently look for the personality of a writer is a grave mistake. What I think is an even greater mistake is to lump writers into groups based on gender or race.
Many writers are categorised as 'women' writers, 'black' writers or 'gay' writers. This is always a referent for their work. Their writing might not even touch on feminist or racial issues. Both women and racial groups have been subjugated for so long that people assume that their writing must express a sense of injustice. It might even be covertly sexist or racist to assume this. It even implies that the 'standard' writer must be white, straight and male. Anyone who isn't must explicitly write about their particular experience.
Ralph Ellison always claimed that it bothered him that he was labelled a black writer. The only way people gauged his work had to be through issues of racial identity. Writers like Ellison were always expected to be political, even partisan, in their work. They were virtually expected to carry placards proclaiming 'I am a black writer - I stand for civil liberties.' Just being black seemed to preclude spiritual and metaphysical topics, which writers like Ellison were greatly interested in.
We should see consciousness as a universal human attribute. It might be banal to say that, but it needs to be emphasised. Writing should represent the Platonic Idea. Ideas and linguistic symbols are universal. All abstract predicates belong to these universal concepts. Concepts like 'beauty,' 'justice' and 'freedom' are universal. It would be silly, and patently racist and sexist, to claim that only certain races and genders can write about these universals.
We should not see writing, then, as purely personal expression. It often is. But it is intellectually lazy to claim that Dostoyevsky is a crypto-murderer and that Vladimir Nabokov is a pedophile. The Romantic idea of an artist as a artistic genius stamping is individuality into every page should be dropped. Writing is fun because you get to play around with language and ideas. The Romantic idea of 'the artist as genius' seems to presuppose that the author has moral authority. He does not.
On the other hand, Ronald Barthes and his gaggle of post-modernist friends can get too carried away with their line of argument. They claimed that 'the author is dead' and that we should treat writing as forensic scientists methodically analysing grammar and semantics. One's writing style in itself is very personal and past experience can shape the content of writing. Although academics would rather not think about it, this is a significant aspect which shapes the writing. This way of reading texts also ignores historical readings. The socio-economic/political background of a text is always a crucial factor.