The Food and Drug Administration on Thursday formally endorsed the meat and milk from cloned cattle, pigs and goats as safe, but the agency's 678-page report failed to satisfy critics who cite concerns rooted in ethics, not science.
"Neither the agency nor animal scientists are qualified to tell us whether and when it is ethically acceptable for humans to alter the essential nature of animals," said Carol Tucker Foreman of Washington-based Consumer Federation of America's Food Policy Institute.
She and others said it was time for a national discussion on whether tailor-making animals in laboratories was wise.
"Congressional hearings might start a robust societal dialogue on those issues," said Gregory Jaffe, biotechnology director at the Center for Science in the Public Interest.
Polls show Americans are hardly clamoring for bacon cheeseburgers made from cloned animals or their offspring. In a survey released this month by the Pew Initiative on Food and Biotechnology, 64% of respondents were at least somewhat "uncomfortable with animal cloning."
Such sentiments were outside the scope of the FDA's scientific review. The agency's Center for Veterinary Medicine focused on the health of cloned animals and their progeny, tracking them with physical examinations and blood tests and comparing the results with animals bred conventionally. Researchers also conducted detailed chemical analyses of meat and milk from clones and their offspring.
"We looked at essential elements like vitamins, fatty acids -- a whole array of different components -- to try to determine if there was any distinguishable difference between foods from clones and their offspring compared to foods from conventionally raised animals," said Stephen F. Sundlof, director of the Center for Veterinary Medicine. "There was no difference."
The report didn't address whether products derived from clones would require special labeling.
Cloning allows farmers and ranchers to create what is essentially a delayed identical twin of a prized animal -- perhaps a dairy cow that's an unusually prolific milk producer or a bull whose offspring make for consistently lean and juicy steaks.
A voluntary moratorium has kept most cloned animals and their offspring out of the food supply. The moratorium will remain in effect until the FDA issues its final ruling, possibly by the end of 2007.
If the report is adopted, the United States will be the first country to approve the use of animal cloning in food production, Sundlof said.
To create a clone, the genes of a normal egg are replaced with DNA from the desired animal. An electric shock induces the egg to grow with the copied genetic material; the egg is then implanted into a uterus.
Cloning is simply an extension of assisted reproduction technologies that ranchers have been using since the 1950s, said Amy Iager, co-owner of a midsize dairy farm in Fulton, Md.
Because clones are expensive to produce -- about $20,000 -- they are used primarily for breeding; their offspring head to slaughterhouses or milking barns.
The FDA's risk assessment found that cloned animals were more likely to have birth defects and other life-threatening problems in utero or shortly after birth. But those problems have been seen with other breeding technologies as well; and current federal inspections would keep any unsuitable animals out of the food supply, Sundlof said.
In fact, he said, there's no reason to treat a clone differently from the rest of a herd.
That conclusion makes consumer advocates fear that products from clones will wind up in grocery stores and restaurants without special labeling that would give shoppers the opportunity to avoid the products.
Sundlof said the FDA could only require labeling if a food contained a harmful substance or lacked an essential element -- neither of which appears to be the case with cloned animal products. Still, he said, the agency will hold off on making a decision on labeling until it reviews public comments received over the next 90 days.
Some producers may be able to advertise that their products are not derived from cloning, just as milk producers can say that their animals were not treated with supplemental bovine growth hormone, he said.