First of all, no meat or dairy products from cloned animals are on the market in the United States, so you don't have to worry about it for the time being. You may have heard about a recent study that compared meat and milk from cloned cows to meat and milk from animals that were the products of normal reproduction. The study, published in the April 12, 2005 issue of the Proceedings of the National Academy of Sciences found essentially no differences.
Cloning utilizes the DNA of a single parent and is meant to produce an animal that is identical to the parent. For this study, researchers from Japan and the University of Connecticut cloned a prized Japanese black breeding bull of a type known for superior meat. The comparison cattle were produced by inseminating cows with semen from the son of the Japanese bull. The dairy cow clones were from a Connecticut Holstein cow that produced a lot of milk.
The researchers looked at more than 100 components of beef and found that the only significant difference was that the meat from the clones had a slightly higher fat marbling content than the meat from the comparison cattle. After analyzing the protein, fat, lactose, and solids in the milk, they found no significant differences between the milk from the cloned cows vs. the controls.
The FDA will look at these findings when it reviews research on food from cloned animals; it is supposed to release its own evaluation of the safety of cloned food soon.
Proponents of cloning claim that it will result in better quality meat - more cattle will be produced from prize steers - and better milk production. But last year a report from the National Academy of Sciences (NAS) concluded that current methods for testing the safety of cloned meat and milk aren't good enough to determine the potential health risks. The NAS report also said the testing methods couldn't determine what factors, such as DNA or the presence of certain amino acids, are relevant for predicting the impact on human health.
I think we are a long way from seeing cloned animal products in our supermarkets.
Andrew Weil, M.D.