Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, October 24, 1993 TAG: 9310240096
SECTION: NATIONAL/INTERNATIONAL PAGE: A-1 EDITION: METRO
SOURCE: The New York Times
DATELINE: LENGTH: Medium
The scientist, Dr. Jerry L. Hall of George Washington University Medical Center, reported his work at a recent meeting of the American Fertility Society.
The experiment was not a technical breakthrough, since he used methods that are commonly used to clone animal embryos, but it opens a range of practical and ethical questions.
For example, since embryos can be frozen and used at a later date, it could be possible for parents to have a child and then, years later, use a cloned, frozen embryo to give birth to an identical twin.
Hall is in the in vitro fertilization program at George Washington University, in which doctors help women have babies by mixing sperm and eggs in a laboratory and implanting the embryos in the women.
He was trying to devise a method to create more embryos to implant when couples do not produce a sufficient number of eggs for fertilization. The embryos used in the experiment, at the stage of just a few cells, were not usable for technical reasons and were discarded.
Hall and Dr. Robert Stillman, director of the in vitro fertilization program, declined to be interviewed. In a summary of a scientific paper Hall presented Oct. 13 at a meeting in Montreal of the American Fertility Society, he wrote that by splitting the embryos into twins, triplets or quadruplets, doctors could try to implant more embryos, increasing the woman's chance of becoming pregnant.
Cloning occurs naturally in human beings in the case of identical twins.
A technique has been developed for making identical twins in animals such as cattle by dividing the embryo and letting the new cell clusters develop into genetically identical organisms.
Scientists who routinely clone animal embryos said cloning human embryos should be just as easy.
Dr. Robert McKinnell, a professor of genetics and cell biology at the University of Minnesota, explained that it is much harder to take a cell from an adult and use it to make embryos or even clones, since the cells of adult organisms are committed to specific functions and have switched off their capacity for full development.
"If you live to be 100, a liver is a liver, and it doesn't turn into brain, and it doesn't turn into muscle," McKinnell said.
Ethicists said the very fact that this type of cloning is easy makes the question of human clones so intriguing.
One "Brave New World" scenario is that parents might be able to save identical copies of embryos so that, if their child ever needed an organ transplant, the mother could give birth to the child's identical twin, a perfect match for organ donation.
Or parents could keep a frozen embryo as a backup in case their child died, so they could create the perfect replacement.
Several infertility experts, who run in vitro fertilization programs, said they have no intention of cloning human embryos even if it is feasible.
In fact, said Dr. David Meldrum, the director of the Center for Advanced Reproduction in Redondo Beach, Calif., it would have been better if Hall's experiment had never been discussed.
"It is not a good thing to talk about cloning human embryos," he said. "The public, I think, feels uncomfortable with meddling with the life-producing process. They will see this as one more step along a slippery slope toward more and more meddling."
by CNB