久久亚洲国产成人影院-久久亚洲国产的中文-久久亚洲国产高清-久久亚洲国产精品-亚洲图片偷拍自拍-亚洲图色视频

Scientists defend human cloning plans
( 2001-08-08 11:14 ) (7 )

Scientists determined to create the world's first cloned babies defended their plans on Tuesday against charges from animal cloning experts that the technology was too dangerous to apply to humans.

Vowing to take steps to avoid babies being born with severe abnormalities, Italian doctor Severino Antinori told a contentious meeting of a National Academy of Sciences panel that he would proceed with plans to provide cloned children for infertile couples.

The panel is gathering information for a report expected by the end of September on whether the United States should impose a moratorium on human cloning, which the US House of Representatives voted last week to outlaw.

Antinori and Panos Zavos, a Kentucky fertility specialist working with him, faced tough questioning from scientists who have cloned animals and found extremely high rates of defects and failures.

Zavos said he and Antinori planned to begin the process of creating cloned babies for infertile couples by November. Antinori gained worldwide notice by helping a 62-year-old woman have a child in 1994.

Zavos said he could screen embryos for genetic abnormalities before implanting them, although he acknowledged problems could develop later. His team would inform couples of potential risks and make them sign consent forms, he said.

"We're not perfect but we're trying to get there," he insisted. "This technique can be made safe for people."

Cloning involves taking a living organism and making a virtually genetically identical duplicate. To clone a human, scientists would insert DNA from a person into an egg with its genetic material removed. The egg would be stimulated to divide into an embryo for research or implanting in a woman's uterus.

'NOT GOOD SCIENCE'

Other scientists at the meeting, heavily attended by US and international media, said it was impossible to detect the types of problems seen in animal clones by examining embryos.

"This is not good science," said Rudolf Jaenisch, a biologist and animal cloning pioneer at the Massachusetts Institute of Technology's Whitehead Institute.

Jaenisch and Zavos repeatedly interrupted each other, with Zavos at one time protesting, "I'm not going to let him lecture me."

Jaenisch noted that only 1 percent to 5 percent of cloned animals survive to birth and some of those later die prematurely due to various birth defects. Others are abnormally overweight. Problems occurred at similar rates among cloned sheep, cows, mice, pigs and goats, Jaenisch said.

Other researchers said many animal clones were healthy and predicted that cloning would become more efficient. They said it would still be unethical to try experiments on humans.

Brigitte Boisselier, a biochemist and member of a group known as the Raelians, who also has announced plans to create cloned babies, said people had the right to use their genes the way they wanted. She said that included the right to reproduce one's self by cloning.

The Raelians, who believe in extraterrestrials, promote cloning as a chance for "eternal life."

'HUGE DEMAND'

Boisselier said there was "huge demand" for cloning services because the technology offered infertile couples the hope of having a biologically related child.

"If there are hopes, if there is technology, you should be aware this will be done," she told the panel.

Some panel members asked whether there was anything that could stop the groups from going ahead with human cloning. The teams have not disclosed where they will do their experiments other than to say it will be somewhere the practice is legal.

"Is there any risk too great or any reason too trivial for you not to attempt human cloning?" asked Alta Charo, a University of Wisconsin bioethicist.

The National Academy panel is examining the science behind current cloning research as well as the ethics. Some critics say it is wrong to produce a person that is not genetically unique, even though the clone would be younger and would grow up in a different time period.

The House-passed ban on human cloning would set punishment of $1 million or more in fines and up to 10 years in prison. It now goes before the Senate.

Many scientists, patient groups and the biotech industry oppose the legislation because it also would outlaw "therapeutic cloning" in which scientists make embryonic clones to get stem cells for potential disease treatments.

US President George W. Bush, who supports the ban on human cloning, is weighing whether to permit federal funding for studies of stem cells, or versatile master cells that hold promise for treating serious diseases, derived from embryos slated for destruction at fertility clinics.