DNF at about 70%. It's been years since I haven't finished a book. I'm such a cold-blooded completionist that I cannot leave anything unfinished. 
 While the premise was interesting, the author fails to provide enough scientific fact to back up his vision, which left me scornful and unable to move past the introduction without questioning everything. Only 1 out of 100,000,000 babies are born female. Okay... so why wouldn't the first solution be to manipulate the chromosomes to ensure all female babies?? I may not be much of a scientist, but surely that solution would have come up. And I get that Zoey and company have been educated in the manner of any dystopian novel character, where Big Brother decides what Truth is, but your reader is not similarly situated and can and will be irritated. If you're going to write science fiction, THINK EVERYTHING THROUGH. It's possible the answers are waiting in the last 30% ... but who can expect a reader to have to endure the first 70% on tenterhooks? 
 Finally the writing style was just mind-numbingly boring. I found myself skimming through chunks of clunky, slow paragraphs just to see if there was something better waiting. There wasn't. Even when the plot picks up and the protagonist is literally slashing people's throats open, I was bored to tears. And even though I love survival novels, where there is no dialogue and little action, when Zoey is crashing through the brush and battling rapists, I started drifting away, imagining myself reading any other novel. There is a real desire for realism here. Yes, I can and will happily suspend my disbelief ... if you keep me interested long enough to explain why such remarkable things can occur. Like why Zoey, who has never used a gun or even had any form of weapons related training, is able to accurately shoot people dead after only one missed shot. 
 Do yourself a favor and skip this one.