Dr. Eric Ball examines a healthy 5-day-old patient in his office in Ladera Ranch, Calif. Ball and colleagues decided this week to take only patients whose parents follow the recommended vaccine schedule. Courtesy of Eric Ball hide caption

itoggle caption Courtesy of Eric Ball

A doctor uses a microscrope to view a human egg during in vitro fertilization (IVF), which is used to fertilize eggs that have been frozen. Mauro Fermariello/ScienceSource hide caption

itoggle caption Mauro Fermariello/ScienceSource