I agree with Mark Clark, but I'm afraid it's a losing cause. In the good old days, a noun had a gender (masculine, feminine, or neuter), and a person had a sex (generally male or female). But somewhere along the line someone thought it was indelicate to use the word "sex" so indiscriminately (there's a pun hidden in there somewhere, I think), and borrowed the linguistic term. It's one of those many examples of an acceleration in the natural evolution of language, probably a result of television and, now, the internet.

Unfortunately, it means one of my favorite jokes is destined for obsolescence: A young woman is filling out a job application. She comes to the item with the word "Sex", accompanied by two checkboxes labeled "M" and "F". After some thought, she checks the "F" box. In the margin, she writes, "I haven't M'd for years."

Aloha,
Mark