Space colonization essay !

Hello there,

I'm a student and I'm in my final year and I wish to do my essay about space colonization.
My first topic is about the planets or planetary bodies that are not suitable for this purpose. Such as planets or planetary bodies outside of our solar system. As I understand it it is simply to far to get within a lifetime, so that sugests we would have to have babies in order to do that. But due to cosmic radiation, this presents a large amount of difficulties. Sperm decrease, damage to egg cells etc.
Even though there are ways to protect ourselves from this radiation, it is not enaugh to allow us to have babies in space. Even if a baby could make it out of the womb we would still have problems protecting it from this cosmic radiation. This and the lack of gravity make it impossible to do so in space. But imagine, if we were able to create an atmosphere on Mars or on any other planet, would THAT allow us to have children? Since the atmosphere should filter a part of this radiation?

Greets!