Interstellar vessel carrying embryos, gametes or digitised DNA in order to raise humans or other modosophonts on arrival using robotic parent surrogates.
The size of the payload of an interstellar ship is extremely important, as a small increase in the mass of the payload can lead to a large increase in the mass of the fuel. So lightweight ships carrying only embryos or gametes were developed, equipped with artificial wombs and robot or vec carers to look after the developing infants when they were 'born' at the destination system. The parental robots in early seed ships were sophisticated devices with artificial bonding emotions and other instincts.
Problems With the Seedship Strategy
There were a number of difficulties at certain colonies with the seedship strategy. At Diwali the synthetic human parent surrogates declined to activate the zygote cargo, creating a society of their own. Since the synthetic humans were equipped with very sophisticated AI minds in order to raise the human children efficiently, they were quite capable of creating a fully functioning society of their own.
At Pandya the robot-parents fulfilled their task very well, and the children were raised to maturity; free from any disease because there were none included in the seedship's databanks. When the first starship from another world landed at Pandya the starfarers brought with them many minor illnesses, to which the Pandyans had no resistance.
At Caph the robot parents were too efficient, creating a population explosion which threatened other systems nearby.