It might be a similar mechanism to children being biologically harmed by being raised in too sterile an environment. But I have no formal training in biology, so it's all rather very "iffy". Ionizing radiation may damage DNA, in a similar manner as other mechanisms.
So the study I posted earlier may have found that a "zero radiation environment" is not really harmful, in comparison.
But that's a pretty wild number; "Naturally occurring oxidative DNA damages arise at least 10,000 times per cell per day in humans..."
It almost sounds like we should be walking bags a jelly, with that much damage.
Of course, you should never trust wiki, and should check their references when they say crazy things like that:
Chapter 16, page 2, DNA Damage, DNA Repair and Cancer
It appears to be true.
hmmm... This might explain my friend Bob. He's kind of a walking bag of jelly.