I don't think the idiom translates to Danish that way. This appears to be meant in a strictly literal sense, with the stem being 'lys', as in 'light', giving us 'glowing'. To say you have an idiomatically 'bright' child would be more along the lines of' 'et klog (clever) barn'.
In that case, I would say, Why indeed? Does Denmark have nuclear power plants?
No, for environmental reasons Denmark eschews nuclear power (in favor of coal power...).
No they don't have ! But it's no big deal, nuclear does not make things glowing :D !
Regarding cancer, the amount of burned trash and coal more than makes up for the risk of an NPP meltdown.
Should try investing in an ITER-style one.
"Lysende" can indeed mean brilliant in Danish. Just watch any "Olsenbanden" film!
I can't translate "barn" as "baby"? Is that always either "baby" or "spædbarn"?