Embryo space colonization is an interstellar space colonization proposal that involves sending a robotic mission to a terrestrial planet (having a biosphere) that transports frozen early-stage embryos. Fully autonmous robots would build the first settlement on the planet and start growing crops. Thereafter the first embryos could be defrozen and would have to develop in an artificial womb.
In contrast to a generation ship, an EIS (Embryo-carrying interstellar starship) would have feasable small dimensions in the range of today's spaceships.
The EIS-concept circumvents the problem of freezing living humans (that is technically not possible today and is regarded by many scientists as never to be possible- see cryonics) and use the currently feasable way of preserving human embryos in a frozen state to overcome the problem of a space voyage of hundreds or thousands of years.
Major obstacles that the plan of an EIS faces are the development of fully autonomous robots, the creation of an aritificial womb as well as computer hardware that functions over a period of hundreds of years. Furthermore a propulsion system that can accelerate the EIS to a speed of around 1 % lightspeed and slow it down again at the destination is required (this supposes the existence of an exoplanet qualifying for colonization within 100 light-years of Earth).
Beside these technical problems, ethical consideration might arise considering the risk of such a project and the number of embryos needed to colonize another planet.
Examples in fiction
James P. Hogan's novel Voyage from Yesteryear features a planet that was colonized many generations ago by an automated ship bearing frozen embryos, and is now being visited by a more advanced interstellar spacecraft capable of carrying an adult crew.
Jack Williamson's Manseed has as a protagonist one of the robots responsible for protecting and assisting colonists created on a new planet by an automated "seedship", though in this case the colonists are "born" as full adults and with implanted knowledge taken from preexisting humans via mind transfer technology.
See also