Jean Couch, 75, perches on the edge of a chair at her home in Los Altos Hills, Calif. She teaches people the art of sitting in chairs without back pain. Erin Brethauer for NPR hide caption

Of parents who tell pollsters their teens have trouble sleeping, 23 percent say the kids are waking up at night worried about their social lives. A third are worried about school. All-night access to electronic devices only aggravates the problem, sleep scientists say. 3photo/Getty Images hide caption

Because of a recent court decision, the size of the financial incentive your employer offers you in hopes of motivating you to lower your cholesterol or lose weight may soon shrink. Molly Cranna/Refinery29/Getty Images hide caption

Walter Mischel, a psychologist who devised the marshmallow test, explained what it really means. Marcie LaCerte/NPR hide caption

"If you do say, 'Yes, my child has seen a counselor or a therapist or a psychologist,' what does the school then do with that?" asks Laura Goodhue, who has a 9-year-old son on the autism spectrum and a 10-year-old son who has seen a psychologist. Andrea D'Aquino for NPR hide caption

Drinking water samples from homes in southwestern Puerto Rico are tested at Interamerican University of Puerto Rico in San German. Rebecca Hersher/NPR hide caption

Immature human eggs (pink) were created by Japanese researchers using stem cells that were derived from blood cells. Courtesy of Saitou Lab hide caption

The fix was in for this rhesus macaque drinking juice on the Ganges River in Rishikesh, Uttarakhand, India. No gambling was required to get the reward. Fotofeeling/Getty Images/Westend61 RM hide caption

Friend or foe? A California two-spot octopus (Octopus bimaculoides) gives observers the eye at the Marine Biological Laboratory in Woods Hole, Mass. Tom Kleindinst/Marine Biological Laboratory hide caption

Preparing for a natural disaster becomes even more complicated when you're expecting. Thanasis Zovoilis/Getty Images hide caption

A Swiss study tracking the health of a group of children conceived via assisted reproductive technology found that a surprising number developed premature aging of their blood vessels. Now in their teens, 15 percent have hypertension. Steve Debenport/Getty Images hide caption

Lt. Ryan Snyder, who works at the Champaign County jail in Illinois, says it's hard for any such facility to provide the kind of one-on-one mental health treatment many inmates need. Christine Herman/Illinois Public Media hide caption

Physicians face long hours, frustrating paperwork and sometimes difficult patients. But researchers aren't so clear on whether burnout is the right word to describe their problems. ERproductions Ltd/Blend Images/Getty Images hide caption

Nearly 62 percent of respondents had at least one ACE and a quarter reported three or more. The remaining respondents had at least two ACEs, including 16 percent with four or more such experiences. Elva Etienne/Getty Images hide caption

Megan Baker (left) of Papa & Barkley Co., a Cannabis company based in Eureka, Calif., shows Shirley Avedon of Laguna Woods different products intended to help with pain relief. Stephanie O'Neill for NPR hide caption

Skull fractures, concussions and broken bones are common injuries when children not yet able to walk use infant walkers and fall down stairs. Mint Images/Getty Images hide caption

Daily low-dose aspirin can be of help to older people with an elevated risk for a heart attack. But for healthy older people, the risk outweighs the benefit. Bruno Ehrs/Getty Images hide caption

Aaron Reid, 20, rests in an exam room in the National Institutes of Health Clinical Center in Bethesda, Md. Rebecca Davis/NPR hide caption

A government research project to assess the safety of BPA is beginning to show results. T-pool/STOCK4B/Getty Images hide caption