Rob Stein

Updated at 4:05 p.m. ET

For the first time, doctors in the U.S. have used the powerful gene-editing technique CRISPR to try to treat a patient with a genetic disorder.

Scientists have created living entities that resemble very primitive human embryos, the most advanced example of these structures yet created in a lab.

The researchers hope these creations, made from human embryonic stem cells, will provide crucial new insights into human development and lead to new ways to treat infertility and prevent miscarriages, birth defects and many diseases. The researchers say this is the first time scientists have created living models of human embryos with three-dimensional structures.

A Russian scientist says he wants to create more genetically modified babies, flouting international objections that such a step would be premature, unethical and irresponsible.

Denis Rebrikov, a molecular biologist who heads a gene-editing lab at the Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology in Moscow, claims he has developed a safe — and therefore acceptable — way to create gene-edited babies.

A congressional committee voted Tuesday to continue a federal ban on creating genetically modified babies in the United States.

The House Appropriations Committee voted to retain the ban after the prohibition had been lifted last month by a subcommittee. The vote was part of debate over routine funding legislation for the Food and Drug Administration.

There are new concerns about the world's first genetically modified babies.

It appears that the genetic variation a Chinese scientist was trying to re-create when he edited twin girls' DNA may be more harmful than helpful to health overall, according to a study published Monday. The study, in Nature Medicine, involves the DNA of more than 400,000 people.

In the hope of finding a new way to fight malaria, scientists have used a spider gene to genetically engineer a fungus to produce a venom that can quickly kill mosquitoes.

The modified fungus was a highly effective mosquito killer in the first tests mimicking conditions in sub-Saharan Africa, where malaria remains a major public health problem, researchers reported Thursday in the journal Science.

The federal Food and Drug Administration has approved a gene therapy for a rare childhood disorder that is now the most expensive drug on the market. It costs $2.125 million per patient.

But for those patients lucky enough to get it, it appears it can save their lives with a one-time treatment.

Three-year-old Donovan Weisgarber is one of those patients. When he was born he seemed perfectly healthy. But within weeks, it became clear something was terribly wrong.

Alphonso Evans rolls his wheelchair into a weight machine in the gym at the Charlie Norwood VA Medical Center in Augusta, Ga.

"I'm not so much worried about dying from a heart attack or diabetes, because I'm active. I know what to do to work against it: watch what I eat, exercise," Evans says. "But what do I do about an infection? Or fighting off a bacteria — something inside me that I don't see until it's too late?"

For the first time, scientists have used genetically modified viruses to treat a patient fighting an antibiotic-resistant infection.

Isabelle Carnell-Holdaway, 17, began the experimental treatment after doctors lost all hope. She was struggling with a life-threatening infection after a lung transplant. With the new treatment, she has not been completely cured. But the Faversham, England, teenager has recovered so much that she has resumed a near-normal life.