Cloning has also been criticized for its effects on the experimental animals. At birth, lambs and calves cloned from embryos can be twice the usual size, creating considerable stress on the surrogate mother.

• 克隆技术给实验动物带来的影响也遭到了批评。从胚胎克隆出来的小羊和小牛出生时是正常大小的两倍，这样给替身母体造成了相当大的压力。