So without giving anything away here, we're given the long awaited answer to the plague. Well, it looks that way at this point. Anything can happen with this series (I don't mean that in a bad way). When I was finally shown the reason, it really didn't matter.
Let me clarify. Obviously the reason behind the "gendercide" needs to be given to the audience. It's just that Vaughan has created these characters that are sticking with me. Some people may have problems with the big reveal and I can certainly understand that. In fact, my favorite book of all time The Stand, has a pretty ridiculous ending. However, just like the characters in The Stand, it's the journey that these women, and Yorick, have been on that make this series so great.
Geez, I'm acting like the series is finished! I still have another damn book to read!
I wasn't crazy about the re-appearance of a long lost character at the end of the novel. I assume Vaughan has plans for her in Book #10, I mean, if not - kind of pointless?