Michele Pereira, who questions the schedule of mandatory vaccines, sat with her daughters, Evangeline, 6, right, and Genevieve, 2, at a park in Ashland, Ore., earlier this month. Jeff Barnard/AP hide caption

itoggle caption Jeff Barnard/AP

Cholesterol-fighter simvastatin, the generic version of Zocor, gets a clean bill of health in an update to a study dating back to '90s. JB Reed/Landov hide caption

itoggle caption JB Reed/Landov

H5N1 avian flu viruses (seen in gold) grow inside canine kidney cells (seen in green). Cynthia Goldsmith/CDC hide caption

itoggle caption Cynthia Goldsmith/CDC

The most common cause of brain injury in premature infants is a lack of oxygen in the days and weeks after birth, researchers say. Ibrahim Usta/AP hide caption

itoggle caption Ibrahim Usta/AP

Tokay Geckos, like this one perched on a twig in suburban Quezon City, Philippines, are being hunted and killed to satisfy booming demand for them as an ingredient in alternative medicines. Bullit Marquez/AP hide caption

itoggle caption Bullit Marquez/AP

Republican presidential candidate Gov. Rick Perry of Texas prepares to speak at a dinner in Bettendorf, Iowa, Monday. Two years ago Perry signed into Texas law an insurance mandate covering controversial tests for heart disease. Charlie Neibergall/AP hide caption

itoggle caption Charlie Neibergall/AP