Min Chueh Chang - Professional Achievements

Professional Achievements

One of Min Chueh Chang's most notable achievements in terms of pragmatic means was his research and testing of the effectiveness of certain steroids in the control of mammalian fertility when the steroids were administered orally. This was to lead to his co-invention of the first birth control pill with Gregory Pincus. Chang is arguably most remembered for this endeavor as the birth control pill came to have a tremendous influence on human society and the sexual revolution. However, controlling fertility was not the primary concentration of his work. Chang's interest lay in sperm, eggs, and the fertilisation process itself. The ability to control the fertility of eggs was a necessity to his work. He initiated the study of orally administered contraceptives for mammals to enable him to better conduct his research in fertilisation. Indeed, throughout the span of his 45-year career, only five years, 1951 to 1956, were spent researching and testing the effectiveness of orally administered contraceptives, and this work was mainly on the oral mode of the administration of the contraceptive steroids, rather than on the effectiveness of the steroids themselves, which had already been previously proven.

Chang's body of work in mammalian fertilisation is vast and appears in nearly 350 publications. One of his major discoveries was the effect of lowering temperature on sperm. Chang found that at a temperature of 13 °C or lower, the membrane structure and function of sperm would disintegrate, thus destroying the fertilising capacity of the sperm. This phenomenon is now commonly known as cold shock. Yet another of Chang's major discoveries was his observation on the relationship between the number of available sperm and the effective fertilisation of ova by the sperm. It was believed that the fertilisation of the egg was dependent on there being a very large number of available sperm in the fertilisation process. Chang found that it was actually the physiological structure of the individual sperm that affected the actual fertilisation of the egg, and that having a large number of sperm was not necessary. He then posited that the purpose of having a large number of sperm in the fertilisation process was to allow for greater genetic recombination, in that only the strongest sperm would reach the site of fertilisation through the female reproductive tract. The process of capacitation, the maturation period of sperm that is required in order for them to be able to fertilise ova, was also amongst one of Chang's major discoveries. This observation would lead him further to find that capacitated sperm would lose capacitation if exposed to seminal plasma or blood serum, and that recapacitation could be achieved if the sperm was placed back in the uterus or the fallopian tubes.

Of all his research and experimentation, Chang's work in in vitro fertilisation was arguably his greatest achievement. In 1935, Gregory Pincus had claimed to have achieved successful mammal birth from the result of in vitro fertilisation of rabbit eggs. As nobody, including Chang, could repeat this feat at the time, doubts were cast over the authenticity of the claim. Then finally, in 1959, Chang in vitro fertilised a black rabbit's eggs with a black rabbit's sperm, transferred them to a white rabbit, and was able to produce a litter of young black rabbits. This was the sort of evidence attesting to the feasibility of in vitro fertilisation for which many scientists had been searching. In the years that followed, Chang and his associates conducted further research to determine specific conditions of successful in vitro fertilisation as well as to perform the technique on other mammals such as hamsters, mice, and rats. It was on the basis of Chang's findings that the first in vitro fertilisation of human eggs was performed, leading to the birth of the world's first "test tube baby" in 1978.