There are a lot of readers who have really liked this book, so this may be one of those situations where it's not the book, it's me.
I just can't deal with the world-building. I am so over dystopias where misogyny is a cheap and easy substitute for putting together a world that makes sense. This book has significant parallels to The Handmaid's Tale (a bloody brilliant book, btw) without the necessary theological underpinnings that make The Handmaid's Tale so terrifyingly plausible.
Basic premise: men are in charge and women are enslaved as baby breeders in a world where, for reasons that are completely unclear, fertility has significantly declined. And here is where my problems with the world-building really begin.
Because it doesn't actually make sense that virginity would be a prized commodity in a world where fertility has declined. In fact, it would make much more sense that a proven ability to bear children would be a prized commodity. And, as well, it seems that it isn't so much fertility as a whole that is the problem, but rather, fertility vis a vis male children that has declined.
"Before any sale is final, every girl is forced to have a medical test to determine if she’s pure or not. Magnates—the wealthiest men in the city—pay a lot of money for First Rounders; they want to be the first to own their brand-new toy. Then, when they tire of her, or when she gives them what they really want—a boy child—she’s returned to the Garden and resold as a Second or Third Rounder for childbearing, or pleasure, or anything else, to a man with less money. Her baby, if she has one, is handed over to the Keepers to be raised."
(Oh, and not to put too fine a point on it, but this whole idea of a medical examination that can "tell" if a girl is pure is utter horseshit. No such examination exists. In fact, even in cases of legally confirmed child sexual abuse, the vast majority of examinations are normal (NIH study). (I am sorry to get graphic here, so you may want to skip ahead to the next paragraph.) In addition, studies reflect that young women who become pregnant and, even, give birth can often show completely normal genital examinations. The "hymen" is not a barrier that must be broken during intercourse. It is an elastic, generally donut shaped piece of tissue).
The problem is that anyone with even the slightest knowledge of biology knows that it is the male contribution that determines the sex of a human child. So if women aren't having boys this is because there is a problem with the male reproductive systems. And, sure, individual men throughout history have been able to blame women for their reproductive failures (cough, Henry VIII, cough), but at some point someone with a background in biology is going to point out that they are all completely full of shit, and it is their little swimmers that are the problem here. Because they fucking aren't all the King.
(Also, completely inexplicably, they periodically just kill off a whole shit ton of the women. Which makes TOTAL SENSE in a society with infertility problems. Oh, wait, no it doesn't.)
And then, logically, wouldn't men who are proven to be able to create boy children be the top of the reproductive food chain? And women who are proven to be able to carry boys would also be sought after? Would we not keep the men with the good sperm in breeding farms and use them to produce boy babies? Why, then, would virginity be important?
And there is no theological component to the importance of virginity either. In the historical world, purity was critical because there was no such thing as paternity testing. The only assurance that a man had that his child was his was female chastity, otherwise he would end up with a cuckoo in his nest, giving his land and other shit to the sons of his rivals. This explains everything about where the theological underpinnings of female purity came from - but this book gives us nothing to suggest that there is a theological component to their world. And it is set in the future, so unless they've forgotten how to DNA test, the whole thing is just stupid.
It's a world of douchey men who don't understand biology and enslave women for no-logical reason whatsoever. Misogyny masquerading as world building. And I can't deal.
Edited to add:
There is absolutely nothing wrong with the writing. I will definitely try Simmons again - this book just didn't work for me at all.