An 11-year-old Tennessee boy got a handy Christmas present this year. Gavin Sumner, who was born without a left foot, most of his hands, and with only 40 percent of his tongue, told his mom he wanted hands for Christmas—and he received a pair of customized prosthetic hands during a ceremony at Montgomery County Mayor Jim Durrett’s office in Clarksville, Tenn., on Monday.

Scientific discoveries in 2019 awed and sometimes alarmed us. At the end of last year, Chinese scientist He Jiankui shocked the world with the announcement that he had used the CRISPR gene-editing tool to modify the DNA of human embryos who developed into twin girls. The scientific community continues to grapple with the implications of his rogue experiment, debating what limits regulators should place on developing reproductive technologies.

The crew of the International Space Station won’t receive their Christmas presents as planned. An improperly set clock on Boeing’s Starliner space capsule caused officials to abort its planned weeklong test mission and land it in the New Mexico desert on Sunday. Piloted by a test dummy named “Rosie the Rocketeer,” Starliner was to dock with the space station and deliver presents as well as clothes and food to the crew.

A little more than a year after Chinese scientist He Jiankui startled the world by announcing he had produced the first gene-edited human babies, new and incriminating evidence against him has come to light.

Less than two years ago, scientists at Cambridge University in Britain announced they had engineered artificial mouse embryos from stem cells rather than from an egg and sperm. Ethicists warned the new technique would lead to the production of synthetic human embryos—and it did.

A fossil discovery in Germany defies the bedrock evolutionary belief that humans evolved from ancient, knuckle-walking apes in Africa.

The Tennessee Aquarium is lighting its Christmas tree using an unusual power source: an electric eel. The eel, known as Miguel Wattson, releases low-voltage bursts of electricity while searching for food, aquarist Kimberly Hurt said.

How does it work? A special system connects the eel’s tank to a strand of blinking lights on a nearby Christmas tree. Miguel emits higher voltage shocks, powering brighter flashes, when he is eating or excited.