Word: embryos
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...pregnancy. To perform it, the obstetrician inserts a long thin tube through the vagina into the uterus. A second doctor, following the procedure on an ultrasound monitor, helps the obstetrician position the catheter between the lining of the uterus and the chorion, a layer of tissue that surrounds the embryo during the first two months and later develops into the placenta. The goal is to suction up a sample of the chorionic villi, finger-like projections of tissue that transfer oxygen, nutrients and waste between mother and embryo. "It's like vacuuming a shag rug; you get about half...
Eight days later, University of Pennsylvania Veterinarian James Evans, who earlier this year had supervised another miracle of animal husbandry-the birth of the first "test-tube" domestic cow-flushed five embryos from the gaur's womb. Four of these were transferred into four Holstein cows, selected in part because their calves are larger than gaur calves. Though the reproductive cycles of all five animals had been synchronized with drugs, one cow did not accept the embryo. Another aborted after five months. The third delivered a dead fetus at 9½ months. But two weeks later, Flossie produced...
Others argue that human life does not start until a week or so after conception, when the fertilized egg has traveled through the Fallopian tube and implanted itself in the wall of the uterus. "We are able to discern [the embryo's] presence and activity beginning with implantation," wrote Dr. Bernard Nathanson, former chief of obstetrical services at New York City's St. Luke's Hospital, in his 1979 book Aborting America. "If this is not 'life,' what...
Others pinpoint the beginning of human life when the heart of the embryo begins beating, around the fourth week of pregnancy, or when the central nervous system has developed to the stage where simple reflexes are evident, around the sixth week. By the eighth week, the embryo is undergoing the transition to a fetus and is definitely recognizable as a human being-a stage that some defend as the beginning of human life. Says Dr. Maurice J. Mahoney of the Yale University School of Medicine: "For me, humanness requires that some process of development has taken place which gives...
...alternative method would be to produce and transfer more than one embryo, Biggers said. He added, however, that the modification could result in multiple births. Another method would be the removal of several eggs at a time to allow for repeated attempts at implantation, he said...