Why Colonize Mars?

The characters in Poul Anderson's Twilight World have a reason that we do not. Radiation still permeates their Earth, threatening birth rates and ecological stability. The heredity-control problem must be solved soon but it has become impossible to study genetics in Terrestrial conditions. Many specimens must be studied, too many for sealed chambers which, in any case, cannot be protected from the pervasive radiation.

Mars, easier to colonize than the Moon and not much further away in terms of rocket fuel, will provide suitable laboratory conditions and will also be a more suitable base for the government's eugenics policy which requires resented segregation and privilege on Earth. The colonists will no longer be mutating and will have a better chance of survival if Earth cannot be saved. They will reseed Earth.

Anderson has to provide credible motives for his supermen to travel as a group to Mars but I think that he succeeds.