Powerful New Pot May Harm the Brain, Researchers Say

But marijuana advocate calls the study 'speculative'

Scientists, Ethicists Debate Future of Gene Editing

U.S. summit draws attention to a technology with great potential -- and peril

SIDS Risk Depends on More Than 'Sleeping Environment'

Study finds 'Back to Sleep' messages worked, but so did lower smoking and teen pregnancy rates

Slowed Walking in Seniors May Signal Alzheimer's Danger

Study found higher levels of beta amyloid in brains of those who didn't move as fast as their peers

Survival Improves for Patients With Advanced Breast Cancer

Study finds better prognosis in women whose tumors have spread beyond the breast, nearby lymph nodes

Too Much TV While Younger May Hamper Middle-Aged Brain

Low levels of physical activity also tied to decreased mental function later in life, study finds

1 in 8 American Adults Still Have High Cholesterol: CDC

Many don't meet targets, and expert says even those targets aren't good enough to prevent heart attacks

Cracking Knuckles Sets Off 'Fireworks' on Ultrasound

Bright flash shows up as gas bubble forms in joints, researchers report

Delayed Clamping of Umbilical Cord May Be Better for Preemies

Waiting 45 seconds was linked to enhanced motor skills among infants in study

Doctor Burnout Rates on the Rise

Surveys show a nearly 10 percent increase across a range of specialties in the U.S.