Space is not the place:

The Daily Telegraph reported that the Ames Research Center in California has found that radiation in space will sterilize female embryos conceived there. It also damages male sperm counts.

The way to stop the radiation, made up of high-speed protons, from playing havoc with human fertility, is to develop effective shielding on spacecraft. However, heavy shielding makes getting any spacecraft launched much more expensive.

The findings show that plans to colonize the further reaches of space will have to take this into account.

Making accounts for colonizing another planet or place in space? Let's be clear about this: There is no future for us anywhere else but that which makes up the ground we stand on. Indeed, even if it were to work, even if we were to send a colony to space, which would be at most a tiny fraction of our species, genetic drift and possibly other, unanticipated evolutionary processes would radically transform that colony into something we could never imagine. (It's surprising that science fiction cinema has never explored this possibility—a space colony that begins as human and becomes, by directed and neutral evolution, something other than human, something truly alien.)

Remember, modern humans radiate from one small point—a bottleneck in East Africa. We are new in this world. The human is a revolution.