Setting aside the question of "compared to what?" (I presume they mean "more than normal folk"), I think it's more fun to brainstorm the question of "what could be done to prevent this?"

I'm guessing that the mutation danger is because space is just full of radiation that various layers around the earth give us partial protection from. So what can be done in a hypothetical spacecraft to get the same level of protection?

If we want to send people to Mars, or live in large numbers in space, these are fundamental problems to solve.