The 1990s witnessed a revival of interest in reproductive biology, partly due to the successful application of gamete and embryo culture to medical, veterinary and biotechnology practices, but also due to the pressing needs of today's society. In medical science, assisted reproductive technologies (ART) have been developed primarily to alleviate sterility, while in agricultural sciences the growing needs of the booming world population have provided the impetus to improve the efficiency of livestock production. The earliest documented use of ART was in 1783 when Spallazani delivered pups from an artificially inseminated bitch, but it was not until the 1900s that the Russian School of Ivanov developed artificial vaginas and insemination techniques to be used in horses, cattle and sheep. The value of artificial insemination in farm animals depends upon the fact that the male ejaculate contains many millions of spermatozoa, theoretically sufficient to inseminate hundreds of females. A major leap forward in this direction was made in the late 1940s, when the team led by Chis Polge in Cambridge, England, developed techniques to freeze and store animal spermatozoa. This same period of time also saw the development of methods to isolate and manipulate the female gamete. In vitro maturation of mammalian oocytes was first reported by Pincus over 50 years ago, when it was observed that the primary oocyte of the rabbit resumed meiosis spontaneously when liberated from its follicle and placed in a suitable culture medium.