NEW YORK (CBS) A Chinese researcher tells The Associated Press he helped create the world's first genetically edited babies.
"I feel a strong responsibility that it's not just to make a first, but also make it an example," Dr. He Jiankui said.
Jiankui claims he altered embryos for seven couples during fertility treatments. One resulted in the birth of twin girls this month.
The gene editing was done using CRISPR, a tool that allows scientists to cut DNA apart to disable or fix a certain gene. The goal was to change a gene to prevent HIV infection.
This kind of gene editing is banned in the U.S. because changes can be passed on to future generations and could harm other genes. There are also concerns it could lead to "designer babies" -- allowing parents to choose traits like hair, eye or skin color.
Many experts say the experiments are unethical.
"We still have a lot of work to do to prove and establish the procedure is actually safe. I would say no babies should be born at this time following the use of this technology," said Dr. Kiran Musunuru of Penn Medicine.
There's been no independent verification of the claims, and they have not been published in a medical journal.
The university where the researcher had worked is calling for an investigation, saying he has been on unpaid leave and officials were unaware of the research project and its nature.