Darwin's Children is Greg Bear's sequel to Darwin's Radio, a book I picked up on vacation last year and skipped all food, drink and bathroom breaks until I was done with it. It was that good.
First of all, I think you must read the first book to enjoy the sequel. The story is just too connected. Children is set about 10 years after the births of the Sheva children. The American public has reacted predictably to the births of a new sub-species of human - complete fear and loathing. The politicians also react predictably - concentration camps. They call them "schools."
It is a very good book and a worthy sequel. It's lighter on the hard science and heavier on the touchy feely / interpersonal stuff than its predecessor. And I didn't stay up all night reading it, although I did finish it in under a week.
Like Radio, it is completely believable. If we did start giving birth to a new sub-species of human, I think the reaction would be very much like how it's laid out in this book.