Gender Bender?

Just realized that in my last post, I assumed the irate subway rider was a woman when, in fact, there was nothing in the letter--no name, no signature, no contextual clues--to confirm that assumption.

To me, it usually feels pretty obvious whether the writer is a woman or a man, even if he or she doesn't give any explicit indication--I wonder if it really is as unambiguous as it seems, or if I'm guessing wrong as often as right?

If I were the columnist, I think I'd have a hard time keeping those assumptions out of my answer in cases where the writer has chosen not to specify.