[Effect of weightlessness on the reproductive system of mammals]

This paper summarizes experimental data available about the effect of microgravity on the reproductive system and reproductive function of mammals. The flight experiment on female rats has shown that fetuses can grow and develop when the maternal organisms is exposed to microgravity. The data concerning the effect of microgravity on the reproductive function of mammalian males are limited and controversial. Analyzing them, it can be noted that the changes seen are small and reversible and that cells involved in spermatogenesis show greater resistance to space flight factors than other continuously renovating cell populations. Future approaches to the experimental investigations in this area are discussed. It is emphasized that fertilization and early stages of mammalian development in space flight deserve special study.