Here's a site that let's you put a block of text into a field and it'll guess whether the person who wrote the passage is male or female. It's based on this:
Similarly, what the gender-identifying algorithm picks up on is that women are apparently far more likely than men to use personal pronouns -- ''I,'' ''you'' and ''she'' especially. Men, on the other hand, prefer so-called determiners -- ''a,'' ''the,'' ''that,'' ''these'' -- along with numbers and quantifiers like ''more'' and ''some.'' What this suggests, according to Moshe Koppel, an author of the Israeli project, is that women are more comfortable talking or thinking about people and relationships, while men prefer to contemplate things.
It claims to be correct 80% of the time.