Nearly two-thirds of mutations in human cancers are attributable to random errors that occur naturally in healthy, dividing cells during DNA replication, researchers report in the 24 March issue of Science. Though mutations that cause human cancer have traditionally been thought to originate from heredity or environmental sources, these results — grounded in a novel mathematical model based on data from around the world — support a role for so-called "R" or random mutations in driving the disease.

Intelligent robots supervised by surgeons could help take human error out of the operating room, researchers say.

AAAS this week urged policymakers to support research using donated fetal tissue, which was instrumental to the development of the vaccine to combat polio, and today advances efforts to better understand the Zika virus, eye disease, and human development.