Numerous
physiological changes have been noted during
spaceflight, many of which may affect sex and procreation, notably
circulation and the flow of blood within the body. Such potential effects would likely be caused by a culmination of factors, including gravitational changes, planetary and space radiation, noise, vibration, social isolation, disrupted circadian rhythms, or mental and physical stress.
Gravity and microgravity 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 life, evolved under the constant influence of the Earth's 1
g gravitational field. It is important to study how space environment affects critical phases of
mammalian reproduction and development, as well as the events surrounding
fertilization,
embryogenesis,
pregnancy,
birth, postnatal maturation, and
parental care. Studies conducted on
rats revealed that, although the
fetus developed properly once exposed to normal gravity, rats raised in
microgravity lacked the ability to right themselves. Another study examined mouse embryo fertilization in microgravity. Although this resulted in healthy mice, once implanted at normal gravity, the fertilization rate was lower for the embryos fertilized in microgravity. , no mice or rats had developed while in microgravity throughout the entire life cycle. In 2006, American
novelist Vanna Bonta invented the
2suit, a garment designed to facilitate sex in weightless environments such as outer space, or on planets with low gravity. The 2suit was made of a lightweight fabric, with a
Velcro-lined exterior, which would enable two people to securely embrace. However, Bonta stressed that the 2suit was versatile, and was not intended for the sole purpose of sex. Functionality testing was conducted in 2008 by Bonta aboard
G-Force One, a
low gravity simulator. It took eight attempts for the two test participants (Bonta and her husband) to embrace one another. According to science author
Mark Thompson, the 2suit was cumbersome but moderately successful, and it is not clear whether or not it will have practical value for future space travelers. The 2suit has been covered in the TV series
The Universe as well as a 2008
History Channel television documentary. It has also been discussed by online writers. ==History of attempts==