I think I'm going to allow myself a completely biased review. I'm going to be utterly, shamelessly gonzo. 
 Just a warning, though: This is mostly a character study. Only the end proffers up a choice. 
 The rest of the time, we're given to enjoy two characters who are the same woman, Pat and Tricia, who both live in completely different realities and who make very different choices, but she they later begin to bleed together into one consciousness, but only later in life. 
 Sound like it's up your alley? There's very little action besides living a life or two, full of happiness and unhappiness, tragedies and triumphs, and, as the title implies, a lot of children. 
 So what is this novel, then? It's deceptively simple and oh so horribly complex at the same time. From the surface, it's utterly charming and a perfect joy to read, letting us see different sides of not just Pat/Tricia, but so many other people as well, surprising us with the sheer multitude of directions that any of us could have taken at any point, if things were just a little bit different. 
 Like the ideas that a more permissible social world could exist and lead naturally to higher technological progress, or how a more repressed world could paradoxically promote wider peace, nothing is entirely clear-cut, but it was great to see our world butt-up against another with moon colonies and an actual Mars mission by today's date. 
 Don't get me wrong. This novel isn't precisely an alternate history novel. There are background elements of it, but the real importance is all character-based. :) She isn't important, so she says, but I choose to read the novel in a slightly different way. 
 Under the surface, I see a lot of implications and near-wish fulfillment, an alternate and glorious escape from some of the less-talked about horrors of our world: Agism, age-related memory problems, the assumption that older people can go crazy based on an outside view, but perhaps it's all MUCH different in reality. Maybe those old people are only behaving that way because they're combining completely different realities and getting confused, naturally, because they both happened. 
 It's so beautiful. It's revolutionary. Hell, I may not look at another old person the same way again. Because... WHAT IF???? Amazing. Cool. YAY! 
 This may be a wonderful character study of a novel, full of so much coolness and real people, but more than that, it's doing something only the very best SF can accomplish. 
 It surprises and makes us wonder. 
 So after all this, I'm telling you, dear reader, that this book KICKS BUTT! :) :) :)