If you were to have children on Mars, what would you tell them is your favourite memory of Earth?
While Mars One has advised against having children on Mars initially, of course procreation is an indispensable part of any colony. Fascinatingly, the genetic changes that occur in subsequent generations of colonisers due to the Martian environment will, eventually, result in genetics distinct from those of humans on Earth.
But evolution happens subtly, little by little. I think my favourite memory of Earth would be how lucky I was to be able to breathe the air and feel the wind and sun on my skin. It's only thoughts of leaving Earth that cause one to realise that each human body and indeed every living thing on Earth is nothing less than the perfect result of billions of years of the evolution of life on our planet.