For me, this was one of those books you come to having heard starkly contrasting opinions about it, that leaves you with confused expectations and wondering what could be so divisive. But now, having finished it, I have to say I didn't find it divisive at all and am left wondering whether the book's harshest critics were even reading the same book.
This was great, well written, thought-provoking SF that explores one of the more interesting themes in SF; how important is individuality and how should the needs of the individual be reconciled with the needs of society.
Humanity is threatened with extinction due to everyone becoming sterile but one particular group of forward-looking individuals develop cloning technology believing that after a few generations, humanity will regain their fertility. The problem is, the new generation of clones are not so sure that they want to go back to propagating the old way and that humanity can be vastly improved if it doesn't.
I loved this book but evidently it's not for everyone. The thing is I'm not really sure why. Often when you read a book, you can see why it might not be everyone's cup of tea. But personally, I can't see why anyone who enjoys thoughtful SF would not get a lot from this book. I know I did.