Katie Pope Kopp, 64, of Parkville, Mo., at Union Station in Kansas City this week. Kopp underwent a new form of experimental CAR T-cell therapy that used the CRISPR gene-editing technique to treat her non-Hodgkin lymphoma. The cancer has been in remission for over a year. Barrett Emke for NPR hide caption
Carlene Knight, who has a congenital eye disorder, volunteered to let doctors edit the genes in her retina using CRISPR. Franny White/OHSU hide caption
A female Anopheles mosquito, a common vector for malaria, feeds on human skin. In a landmark study, researchers showed that genetically modified Anopheles gambiae mosquitoes could crash their own species in an environment mimicking sub-Saharan Africa, where the malaria-carrying mosquitoes spread. Dunpharlain/Wikimedia Commons hide caption
Patrick Doherty volunteered for a new medical intervention of gene-editor infusions for the treatment of genetically-based diseases. Patrick Doherty hide caption
Carlene Knight, 54, is one of the first patients in a landmark study designed to try to restore vision in those who have a rare genetic disease that causes blindness. Josh Andersen/Oregon Health & Science University hide caption
Victoria Gray (second from left) with children Jamarius Wash, Jadasia Wash and Jaden Wash. Now that the gene-editing treatment has eased Gray's pain, she has been able be more active in her kids' lives and looks forward to the future. "This is really a life-changer for me," she says. Victoria Gray hide caption
Victoria Gray, who underwent a landmark treatment for sickle cell disease last year, has been at home in Forest, Miss., with her three kids, Jadasia Wash (left), Jamarius Wash (second from left) and Jaden Wash. Victoria Gray hide caption
Scientists at the Casey Eye Institute, in Portland, Ore., have have injected a harmless virus containing CRISPR gene-editing instructions inside the retinal cells of a patient with a rare form of genetic blindness. KTSDesign/Science Photo Library/Getty Images hide caption
Victoria Gray, who has sickle cell disease, volunteered for one of the most anticipated medical experiments in decades: the first attempt to use the gene-editing technique CRISPR to treat a genetic disorder in the United States. Meredith Rizzo/NPR hide caption
As part of a clinical trial to treat sickle cell disease, Victoria Gray (center) has vials of blood drawn by nurses Bonnie Carroll (left) and Kayla Jordan at TriStar Centennial Medical Center in Nashville, Tenn. Meredith Rizzo/NPR hide caption
As part of a clinical trial to treat sickle cell disease, Victoria Gray (center) has vials of blood drawn by nurses Bonnie Carroll (left) and Kayla Jordan at TriStar Centennial Medical Center in Nashville, Tenn. Meredith Rizzo/NPR hide caption
The preliminary results described Wednesday come from two patients with multiple myeloma and one with sarcoma. This was just a first safety test, the scientists say, and was not designed to measure whether such a treatment would work. Jure Gasparic/EyeEm/Getty Images hide caption
Scientists are exploring a new technique, called prime editing, that is more precise than CRISPR and which uses certain enzymes, including reverse transcriptase, to edit DNA. Evan Oto/Science Source hide caption
Scientists use a microscope to see if the genetic modification is spreading. Immature modified mosquitoes glow red with yellow eyes when illuminated with a laser. Pierre Kattar for NPR hide caption
Although Gray will finally go home to Forest, Miss., she will return to Nashville once a month for four months to undergo blood tests and a bone marrow biopsy. But, she says, the hardest part is over. Meredith Rizzo/NPR hide caption
Gianpiero Palermo, a professor of embryology at Weill Cornell Medicine, runs the lab where scientists are trying to use CRISPR to edit genes in human sperm. Elias Williams for NPR hide caption
Gray was diagnosed with sickle cell disease when she was an infant. She was considering a bone marrow transplant when she heard about the CRISPR study and jumped at the chance to volunteer. Meredith Rizzo/NPR hide caption
CRISPR technology already allows scientists to make very precise modifications to DNA, and it could revolutionize how doctors prevent and treat many diseases. But using it to create gene-edited babies is still widely considered unethical. Gregor Fischer/picture alliance via Getty Images hide caption