Genetic Issues, Besides Cloning, That Lie Ahead

April 18, 2002 -- Rather than leaving it to fate, a 30-year-old woman recently selected which among a batch of her eggs she wished to become her child.

By genetically screening 23 eggs and deciding which ones to fertilize, some might argue the woman and her doctor "played God." But her baby was born free of the mother's genetic curse of early onset Alzheimer's.

Medical breakthrough or genetic quagmire?

As the case, announced by a Chicago doctor in February signals, human cloning is hardly the only genetic ethical dilemma that the nation's scientists and lawmakers face. The Senate is now considering whether to vote with the House and ban human cloning, but other issues surely lie ahead.

For example, how should government regulate a possible market in cloned pigs that are harvested for human transplants? Should athletes be permitted to improve their performances through "gene doping?" And should scientists be able to incorporate chimpanzee or chimpanzee-like genes into people to help fight disease? Looming further in the future is the possibility of parthenogenesis, or virgin birth, and whether women should be allowed to conceive with the help of science, alone.

More Genetic Legislation?

"This is a very volatile time in biomedical research," said Thaddeus Golos, a genetic researcher at the Wisconsin Regional Primate Research Center. "What was science fiction five years ago is now moving into the marketplace."

In fact, some lawmakers are well aware that today's debates on human cloning are only a prelude of many more to come. Rep. Dave Weldon, R-Fla., for example, foresees state or federal government getting involved in regulating genetic manipulation of unborn children.

"There are many many other issues besides human cloning," said Weldon, an internist with a background in molecular genetic research who voted to ban human cloning in the House vote. "Some of the issues we're going to wrestle with will depend on whether the Senate passes the bill banning human cloning or not. One issue can quickly lead to another."

Below are a few fields of genetic research that may soon be facing legal and ethical scrutiny.

What Lies Ahead

Genetically Groomed Athletes: H. Lee Sweeney of the University of Pennsylvania has created a line of "mighty mice."

The rodents feature ripped muscles in their legs and are 20 percent stronger than their former selves — even after no exercise. With a little exercise, the mice increased their strength by 30 percent. What's more, they don't lose their added strength as they age.

Sweeney created the mice with an eye toward helping the elderly maintain strength late in life and possibly helping those with muscular dystrophy. But he's also aware it could trigger a new kind of illicit enhancement among athletes.

"It amazes me how safety is not as important to many athletes as performance," he said.

To enhance his mice, Sweeney injected them with a virus that "infected" the rodents' muscles with a synthetic gene. The gene, in turn, instructs the muscles to produce more insulin-like growth factor-1, which adds muscle.

So far Sweeney has tested the procedure on mice and rats and he hopes to try it on dogs. It's not close to being ready to try on people, he says, but that hasn't stopped athletes from calling him.

"I've been approached by many athletes who are interested in trying it out," he said. "I turn them away immediately."

Still, Sweeney thinks the technique, which is also being developed by other researchers, will eventually find its way into competitive sports.

Then, he projects, it will be tough to screen against since it can't be detected through blood or urine samples. The only way to test for gene doping would be through muscle biopsy — a painful procedure.

Pig Organs: The effort to create pigs with organs for safe transplant into people is already well under way.

In January, two companies announced they had cloned pigs so their organs would meet less resistance if transplanted into a person. The pigs were missing a gene that codes for an enzyme, which past experiments show, triggers rejection from a human implant patient.

Julia Greenstein, CEO of Immerge, one of the cloned pig companies, projects kidney and possibly heart transplants from specially designed pigs, will be possible within five years.

But there are concerns.

Pigs contain viruses called porcine endogenous retroviruses, or PERVs, which some scientists fear could infect human hosts and introduce dangerous diseases. Some pathogens that are harmless in one animal, can be deadly in another.

One of the most notorious examples is AIDS, which is believed to have been transferred from monkeys to people through the HIV virus.

"These retroviruses are attached to the genetic structure of the pigs," said Michael Fox, a veterinarian and animal rights activist. "We could be opening a real Pandora's box here."

Chimp Genes: In an effort to understand what makes us human, scientists have long been interested in our closest genetic relative — the chimpanzee. The research also holds medical promise.

By genetically modifying laboratory chimpanzees, researchers hope to zero in on the exact function and importance of a number of genes that also occur in people. Some even think that people may eventually borrow chimpanzee genes to enhance our own bodies against disease.

Last September, Thaddeus Golos of the Wisconsin Regional Primate Research Center and his team managed to insert a marker gene into two fertilized rhesus monkeys. The experiment was a test run in his plan to create and use genetically modified monkeys to understand what roles genes have in pregnancy and reproduction.

"You can't do these experiments in women, but eventually we can turn off these genes and find out if there's a failure — in monkeys," said Golos.

Monkey models might also help scientists understand why the animals aren't susceptible to symptoms of AIDS or malaria while people are. Golos is cautious about suggesting we might eventually introduce chimpanzee genes into people to help fight disease, as he says, "the ethical questions are huge."

But others admit it's possible.

"It's conceivable you could transfer a chimp gene into a human," said David Nelson, a biologist at Baylor College of Medicine. "Or you could use the chimp gene as a model to tailor gene therapy."

Fox, who authored Bringing Life to Ethics, argues such experimentation is never justified.

"I regard it as genetic parasitism," Fox said. "We're putting genes into animals to make them even more useful. There are profound ethical ramifications here."

Designer Children, Virgin Births: Most have heard about how human conception could become a made-to-order practice, with parents picking and choosing their future children's sex, height, mental ability and eye color.

But what was once considered a rare scenario of the future, may become widespread, some say, as more and more women seek to delay motherhood.

"I think the next big issue is genetic modification that starts at disease prevention and then goes beyond. That's enhancement," said Ron Green, a professor of ethics and religion at Dartmouth College and an ethics advisor for the biotech company, Advanced Cell Technology.

Green explains the race is on to reliably freeze the human female egg. Right now sperm and embryos can easily be frozen since they're made up of small cells, but researchers have struggled to find safe ways to freeze the egg since it's large and contains a lot of water. A Los Angeles clinic announced this week that they are ready to open the first commercial egg bank. A small handful of other clinics also offer the service, but fertility experts remain skeptical the freezing techniques are reliable.

Once a certain method is found, Green predicts more and more women will begin setting aside their eggs at a young age to have children later in life. That means more couples will be using in vitro fertilization to conceive — and more couples will have the opportunity to select the genetic make up of their children.

"The technology will be so appealing to women, I see selection going up enormously," said Green. "It will definitely be a big issue in our future."

In fact, it's already here — ever since the 30-year-old woman in Chicago screened her eggs to select against early onset Alzheimer's. Screening for disease is one thing, says Art Caplan, a bioethicist at the University of Pennsylvania. Screening for cosmetic purposes is another.

"They're not many steps apart," he said.

Green thinks the issue may be one that's best left to parents to negotiate. But, he adds, if a large majority of couples start screening for boys, the government may need to step in.

He points out another field of reproductive research that might make some uncomfortable is parthenogenesis — or virgin birth. Researchers at Advanced Cell Technology have already prodded unfertilized monkey eggs to multiply as if they were fertilized. It's possible the technique could be someday applied to women.

"Some might consider this a cultural nightmare of Amazon-like women having babies on their own," said Green.

As Caplan said, "The cloning debate is just the beginning."