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: