5. Boston Boston's babies are born into an all-encompassing health care bubble. Massachusetts' universal health care law has made the number of uninsured children in Boston nearly nil and has given pregnant women access to prenatal care through private insurance or public coverage. That's given Massachusetts one of the lowest infant-mortality rates in the U.S. and has made Boston a hub for pediatric medicine. The city has nearly 300 pediatricians and more than 100 pediatric specialists, while Boston Children's Hospital has the world's largest pediatric research center. More than 1,100 scientists at the hospital work on treatments and cures for childhood diseases.