With dreams of settling the high frontier of space back in the news, and with plans for lunar bases and Mars colonies being seriously discussed, one much-neglected issue has become a research priority. Can Human Beings reproduce in space? Sex is indeed possible, and rumors abound about couples already becoming members of the “Zero-G Club.” However, no space colony is going to be sustainable for very long if people can’t have viable children. To that end, the Astronauts on the International Space Station are conducting experiments with human and bovine sperm.

Sperm in space

Along with other supplies, the last SpaceX Dragon delivered samples of human and bovine sperm for experimentation. The bovine sperm will be used as a control for the human variety. The ISS astronauts will use the Microgravity Science Glovebox to determine if sperm can swim as well as they can in Earth’s gravity to fertilize an egg. As anyone knows who was awake during high school biology, after the sex act a man’s sperm swims toward a woman’s egg to fertilize it and thus creates an embryo which, in the fullness of time, will gestate into a full grown baby. Most of the sperm does succeed in making the journey. The one that does will pass along the man’s genetic makeup to the next generation.

The question that the ISS astronauts want to answer is can the sperm fertilize a human egg when in microgravity just as well as they can on Earth? The answer to that question could determine the future of the human colonization of space. Of course, similar experiments will likely be conducted on the moon, with one-sixth Earth's gravity, and Mars, with one-third normal gravity, when astronauts finally get to those two worlds.

Next step, gestation

Fertilization is just the first step in human reproduction. The next step in determining how creating children in space works will be gestation, the process of growing an embryo in a womb into a full grown baby. How will microgravity and later low gravity affect the development of a baby when still in utero?

Could such a fetus be viable? What would the baby be like once born? Could a child born on a space station or another planet live for very long, not to mention visit Earth? Future animal experiments will no doubt gain some insights into these questions. They will help to develop medical interventions, if they prove to be necessary, to ensure that future space settlers can have children, thus spreading human civilization beyond the home planet.