 The primary issue to be considered in off-Earth reproduction is the lack of gravitational acceleration.Life on Earth, and thus the reproductive and ontogenetic processes of all extant species and their ancestors, evolved under the constant influence of the Earth's 1"g" gravitational field.It is imperative to study how space environment affects critical phases of mammalian reproduction and development as well as events surrounding fertilization, embryogenesis, pregnancy, birth, postnatal maturation, and parental care.