Meat and milk from cloned animals are safe, the US Food and Drug Administration (FDA) has concluded in a preliminary report intended to help determine whether the agency should regulate such products. In advance of a public meeting that the FDA's Center for Veterinary Medicine (CVM) will hold on the controversial subject Tuesday (November 4) in Rockville, Md., an executive summary of the full report (which is expected to be released later this year) was posted on the CVM Web site today (October 31).

"Edible products from normal, healthy clones or their progeny do not appear to pose increased food consumption risks relative to comparable products from conventional animals," the executive summary said.

The findings may displease consumer and environmental groups that have campaigned against the sale of food derived from cloned animals.

Industry groups, however, have worked to persuade the agency that the products are safe. Companies including Advanced Cell Technology (ACT) of Worcester, Mass., have given the FDA supporting data, Robert Lanza, the company's vice president of medical and scientific development, said.

ACT has cloned more than 100 cows, Lanza told The Scientist, and "the great majority appear to be happy, healthy, and normal." Most scientists believe that cloned animals' progeny are safe to eat, Lanza added, and the progeny, rather than clones themselves, are the ones likely to be eaten.

Officials at the Washington, D.C.–based Center for Food Safety said it is too early to draw such conclusions. "The analysis and the data on potential safety is not there yet," said Joseph Mendelson, the group's legal director. "It's premature to market this stuff."

A National Academy of Sciences report produced last year at the FDA's request said that there is no evidence that products from cloned livestock are unsafe for consumption, but that more tests were needed.

There are already mixed data on the health and normalcy of cloned animals and their progeny.

"Somatic cloning may be the cause of long-lasting deleterious effects," reported researchers with France's National Institute of Agronomy Research in a 1999 Lancet paper. The calf they had cloned suffered lymphoid hypoplasia and died on its 51st day from severe anemia, making it "the first report of a long-lasting defect associated with somatic cloning," the researchers wrote.

Researchers with Humboldt University in Berlin and other institutions reported in the April 1, 1997, Current Biology that mice may transmit genetic changes associated with nuclear transfer to their offspring. This finding was "striking," the authors wrote, because these types of changes (epigenetic modifications) are normally not believed to be heritable.

Lanza said the scientific consensus today is that indeed, they are not. "Epigenetic differences are reset" to normal when cloned animals conceive, he said. This is relevant to the food issue because consumers won't be eating clones, but only their progeny, he repeated. Industry experts say it would make no sense to eat clones themselves, since a cloned cow costs about $19,000.

Lanza and colleagues reported in the November 30, 2001, Science that they analyzed a series of 24 cloned cattle and found no significant rate of abnormalities.

"We did not observe genetic defects, immune deficiencies, gross obesity, or other drastic abnormalities cited by other researchers," they wrote. "It remains to be determined whether these abnormalities occur in other species and/or are due to differences in nuclear transfer techniques." Two clones also gave birth to normal-appearing calves, they noted.

Regarding cloned animals' health, the new executive summary said that cloning "can pose an increased frequency of health risks to animals involved in the cloning process, but these do not differ qualitatively from those observed in other ARTs [assisted reproductive technologies] or natural breeding."

Michael Appleby, the Humane Society of the United States' vice president for farm animals and sustainable agriculture, said FDA officials seem to be focusing too narrowly on food safety while overlooking ethical considerations.

"That may be the limit of their purview of the subject, but it is clearly not the limit of the relevant questions that can be asked," he said. For instance, he said, society should consider the many embryos that die as a result of cloning.

Also, "cows have been selected for milk production for so long, they carry a huge weight of milk, which causes them leg problems and mobility problems," Appleby said, and compounding the problem, cloners would select among even these successful milk producers for the most productive.

All this is "monumentally unnecessary," given the low food prices this country already enjoys, he insisted.

The FDA has asked companies that clone animals not to introduce them, their offspring, or their food products into the human or animal food supply until the agency has evaluated the products' safety.

"We're waiting on the government to say this is going to be okay to use," Donald Coover, owner and manager of SEK Genetics in Galesburg, Kan., said. Coover has already raised several bull clones in order to sell their semen. "Financially, this is going to be a fairly big deal."