Gosh darn it! With a family crisis and house repairs and trips to the hospital, I just don't have time to do justice to this screed on sexism in rules. Alas. So my series on sex ends not with a bang (so to speak), but a whimper.
But let me offer a couple words and a few links. I really admire the 3E Dungeons and Dragons philosophy towards gender issues, sex, and sexism in game rules. Making frequent use of the seecond person (in spell descriptions, for example) is both a way to draw the reader in and to avoid the whole he/she mess. And the use of iconic characters (Mialee, Lidda, etc.) -- and the associated use of corresponding pronouns when needed -- is another great way to avoid the awkwardness of constructions like "his or her."
John Kim is not as kind to the 3E rules. He offers several case studies in this essay.
For a minor example of sexism in an online D&D Adventure, consider these Mask Campaign Romantic Subplots. Of the seven potential NPC love interests listed, women are more available, while men are more distant and less likely to engage in romance.
And here's a conversation about sexism in rules.
This is the last part of a seven part series on sex in role-play games: