FACTBOX: Timeline and facts about animal cloning

(Reuters) - The U.S. Food and Drug Administration has ruled that milk and meat from certain cloned animals and their offspring are safe to eat.

Proponents of the controversial technology will help create animals that produce more milk, better meat and are more disease-resistant.

Opponents of cloning have urged the FDA to delay its final ruling until more studies can be done on safety of meat and milk from cloned animals.

Below are facts and a timeline about animal cloning:

-Hundreds of livestock animals already have been cloned, but producers and the industry has voluntarily agreed not to sell any foods from cloned animals until the FDA makes its decision.

-Cloned animals are attractive to the industry because ranchers are able to keep their favorite livestock, providing better tasting meat and more milk and eggs.

- A cloned calf can sell for more than $15,000, compared with an average calf that costs less than $1,000.

-Cloning animals involves taking the nuclei of cells from an existing adult animal, and fusing them into other eggs that are implanted into a surrogate mother. The technology produces a biological copy of a normal animal.

Cloning timeline:

1996 - One of the most famous cloned animals, Dolly the sheep, was the first mammal cloned from an adult cell and was born in 1996. Dolly was euthanized in 2003 because of a degenerative lung condition.

August, 2002 - A National Academy of Sciences panel said food and biomedical products from cloned and genetically engineered animals pose no significant health risks, but stronger U.S. government oversight must be implemented to ensure its safety. The study was requested by the FDA.

October 2003-FDA says milk and meat products from cloned cattle, pigs and goats are safe for consumers to eat. The agency also said it would consider the ethical concerns posed by U.S. consumer groups on animal cloning before deciding whether to allow the sale of these products.

November 2003- FDA said it will revisit its preliminary determination that food from cloned animals is safe for consumers after several independent science advisers raised questions about the finding.

December 2006- The FDA ruled in a draft decision in December 2006 that food and milk made from cloned cattle, pigs and goats was safe to eat.

February 2007 - Dean Foods Co, the largest U.S. dairy processor and distributor, said it will not sell milk from animals that have been cloned because of ongoing consumer concerns even if food products from cloned animals become a reality.

December 2007 - The cloning firms ViaGen and TransOva Genetics announce a new database to allow food companies to identify a cloned animal as it moves through the food supply chain from farm to slaughterhouse. The database would make it easier for companies to show consumers their products are not made from cloned animals.

December 2007 - The Senate farm bill included a measure from Senator Barbara Mikulski that directed the FDA to complete further review and analysis before issuing a final cloning decision. A similar provision also was in the multibillion-dollar spending bill that passed in Congress.

(Reporting by Christopher Doering; Editing by Russell Blinch and Marguerita Choy)