Kress's short stories are outstanding. I own one or two of her novels, and they don't do much for me, but I'll walk a mile for her short stories, and this one is as good as they come.
From the effects of cheap energy and nano-engineering on society (covered differently in two stories) to the (or at least "a") logical conclusion of easy embryo implantation, her stories are often frightening (though not "horror") visions of potential futures, and always thought provoking.
Every story comes with an afterword, and after one she says that she felt she hadn't done it justice because it should have been a novel. I beg to differ - these stories all work at the length they are.