The only astronaut couple that flew together, in September 1992, avoided telling anyone they were married. Mark Lee and Jan Davis met while training for a Space Shuttle mission and fell in love. The couple married in secret so they would still be able to travel together on the same mission. Following this event, the previously unwritten rule that couples would not go into space together, was put into writing and formed part of the documents governing the selection of astronauts for particular cosmic missions - couple were officially banned from flying together!
For the scientific community, however, what matters most is not the sexual act itself, but how human reproduction will occur in an environment where the gravitational force is lower than on Earth, as this may affect fertilization, egg implantation, formation of the placenta, and foetus development in the mother's womb. Moreover, there are the deleterious effects of cosmic radiation on DNA and cell reproduction to consider.
Studies with mice carried out during space missions in 2010 and 2011 confirmed that some female mice stopped ovulating, while others that were still able to ovulate released compromised eggs. These findings corroborated results obtained by the Russians years earlier in 1979, wherein male and female rats copulated within a satellite in terrestrial orbit, but no baby rats were born as spontaneous abortions occurred.
To colonize other worlds, however, human reproduction in the space environment must be studied and understood. Otherwise, terrestrial babies will never leave our space cradle - planet Earth.
(English translation of an article published in Portuguese in the newspaper Diário Popular, Pelotas)