Elon Musk is not planning to send humans to Mars. While SpaceX CEO wants an ‘Interplanetary Species” on Mars. Which means that at some point sex and pregnancy has to take place in space and/or in Mars. But how will it work? And is it possible?
Until now no human has reached mars so data on how sex will work there is not available. But believe me, sex in space will be a real hassle. Having intimate relations without gravity is impossible. It will be physically complicated to have sex in zero-G. Even if you try in such a conditions, there is the possibility of space sickness and frankly speaking, it will definitely not be romantic. Microgravity makes it difficult to hold on to each other because you keep floating. You can try by anchoring yourself to something but it can also create blood flow problems that will make it difficult to sustain an erection. Also, in zero-G, the bodily fluids will float like a small droplets and will make it complicated.
According to the estimation by Elon Musk, one can reach to Mars in as little as 80 days and realistically 6 months. So sexual frustration will be a serious problem. Also, according to Sheryl Bishop, a researcher in extreme environments says that sending married couples will complicate the things.
“THE ONLY ETHICAL THING IS THAT EVERY SINGLE PERSON ON BOARD WOULD HAVE TO AGREE TO BE STERILIZED”
Beside space sex, other obstacles also exist. Like Radiation. Musk dismissed the possibility of radiation making humans infertile but it can have disastrous consequences on the genome. Which means the possibility of babies with severe birth defects for the astronauts who are exposed to radiation. So self-sustaining civilization will be difficult.

