A London doctor used genetic screening to help a woman conceive Britain's first baby guaranteed to be free of hereditary breast cancer.
The 27-year-old woman decided to have her embryos screened for an inherited gene that would have left the baby with a 50 percent chance of developing breast cancer. The woman has a long history of breast cancer in her family, and her husband tested positive for the gene.
The embryo screening, called preimplantation genetic diagnosis, entails removing cells from several embryos at the eight-cell stage of development, when they are around three days old. The cells from each embryo are tested for genetic disorders, and any embryo that is found to be free of the screened disorders is implanted in the mother's womb via in vitro fertilization.
Preimplantation genetic diagnosis has given hope to families with long histories of genetic disease. But a number of doctors and ethicists fear this medical milestone could lead to genetic selection, giving parents the opportunity to screen their children for traits like intelligence and attractiveness.
Arthur Caplan, director of the Center for Bioethics at the University of Pennsylvania, said genetic screening poses an ethical dilemma.
"Where is this going to take us in the future? How far will we go in letting people decide their babies?" Caplan said.
Doctors in the United States have already used preimplantation genetic diagnosis to screen for inherited diseases.
Chad Kingsbury carries a gene for deadly genetic colon cancer that has killed two uncles, his mother and his grandfather.
Because he carries the gene, he has an 85 percent chance of getting colon cancer, and his offspring has a 50 percent chance of inheriting the gene from him.
So Chad and his wife, Colby, used preimplantation genetic diagnosis to screen an embryo and implant it in Colby's womb.
The Kingsburys said preimplantation screening allowed them to bring their daughter, Chloe, into the world without any fear that she'd get the disease.
"I've seen what this disease can do firsthand," Chad said. "I've held my mother's hand while she died. I look at my grandma every time I see her and there is an emptiness there. I mean, she's lost all three of her children, and I just, I couldn't do that."
Dr. James Grifo at the New York University Fertility Center was the first doctor in the United States to screen embryos for life-threatening genetic diseases.
Grifo said that fears about designer babies are unfounded.
"I think our ability to do the kinds of things that we fear it can do -- create a class of genetically superior humans, a genetic super race -- just isn't going to happen," Grifo said. "We aren't scientifically sophisticated enough to make decisions about complicated traits."
The Kingsburys said they were only thinking of the health of their child.
"You just want to make a happy life for your child, and I think that's all we're trying to do," Chad said.