It's not a children's book. I probably read this book 20 years ago and it was not a new book then. I'm guessing it was written some time between the 40s and 60s, but that's just a guess. The book takes place in a society where there have been lots of treatments for genetic diseases, so people who used to die before child-bearing age weren't, passing the diseases along, and health of the population was therefore less robust. (Plus possibly the cost of treatment.) So people were only allowed to get medical treatments, vaccinations, etc. if they were sterilized. I seem to recall people living in a sort of health-care ghetto and many people being anti-health care.