On this day, 34 years ago, on May 23, 1991 (April 10, 1991, the world's first test-tube sheep to be cryopreserved and transplanted in vitro embryos was born. On May 23, 1991, the world's first test-tube sheep with cryopreserved and transplanted test-tube embryos was successfully born at the Experimental Animal Research Center of Inner Mongolia University. This sheep that delivered normally at full term is male and weighs 3.2 kilograms. After international online search and verification, this achievement is the first in the world. This is a major breakthrough in livestock embryo engineering since the center won the first fetus in China and the first batch of "test tube sheep" and "test tube cattle" since 1989. The success of this test-tube embryo technology has important practical value in accelerating the process of animal husbandry production, improving sheep breeds, and using sheep test-tube embryos for research on embryo engineering and genetic engineering technologies.