Amber Cooper lives in Modesto, Calif., with her 5-year-old son, Jaden, and her husband, Kevin. She had a liver transplant when she was 10 years old and has to take anti-rejection medication. Deanne Fitzmaurice for NPR hide caption

itoggle caption Deanne Fitzmaurice for NPR

Karlton Hill, 15, was diagnosed with diabetes when he was 12. He works hard to manage the disease: He jogs and does pushups every day; he takes metformin is very careful about what he eats. Leslie Capo/LSU Health Sciences Center hide caption

itoggle caption Leslie Capo/LSU Health Sciences Center

Bring on the caffeine — maybe. antwerpenR/Flickr.com hide caption

itoggle caption antwerpenR/Flickr.com

Michelle Salvini (left) and Terri DiCarlo take a break from work outside the Cornerstone Care clinic in Burgettstown, Pa. Mysterious fumes have repeatedly sickened clinic staffers, forcing them to evacuate the building several times. Maggie Starbard/NPR hide caption

itoggle caption Maggie Starbard/NPR

Karen Lindsfor, a professor of radiology and chief of breast imaging at the University of California, Davis Medical Center, examines the mammogram of a patient with heterogeneously dense breast tissue. Lindfors is among those doctors who say there was insufficient evidence to support the idea that additional screenings would detect cancers earlier. Rich Pedroncelli/AP hide caption

itoggle caption Rich Pedroncelli/AP

Connor Galloway, age 12, was found dead in his bedroom with a belt looped around his neck. Connor's friends admitted to his mother that they'd been talking about playing "the choking game." Courtesy of the Galloway family hide caption

itoggle caption Courtesy of the Galloway family

This illustration shows a device made by MammoSite used to deliver targeted doses of radiation as part of brachytherapy. Courtesy Radiological Society of North America hide caption

itoggle caption Courtesy Radiological Society of North America

Cells gathered during a Pap test. Those on the left are normal, and those on the right are infected with human papillomavirus. Ed Uthman/Wikimedia Commons hide caption

itoggle caption Ed Uthman/Wikimedia Commons

The C. difficile bacteria causes infections that kill about 14,000 Americans each year, the CDC reports. CDC Public Health Image Library hide caption

itoggle caption CDC Public Health Image Library
Alvaro Heinzen/iStockphoto

Ramon Maldonado-Cardenas grimaces as he gets a flu shot from pharmacy student Khoa Truong during a health fair in Sacramento, Calif., last October. Rich Pedroncelli/AP hide caption

itoggle caption Rich Pedroncelli/AP