Nuncle has pretty much explicated what I meant be gender in my "dumped the concept of gender as a grammatical concept" post. What I was saying is that we didn't connect the concept of gender to the concept of sex back in the day. The modern English use of the word gender to refer to sex is, in my opinion, a relatively recent development made possible by the total loss of gender markings in nouns, adjectives, and articles. We knew all about sex (or at least all we needed to to keep making babies and directing the baby making in our domesticated animals) long before there was any notion that gender and sex could be conflated.