Cold war version:-

Hush little baby, don't you fear,
The bomb's not going to go off this year
They all went off last year, you see,
But daddy had built a shelter for me

In that shelter we had to hide
While all the bombs went off outside,
Me and your daddy we came out then
And started the human race again

When you were born it was very clear
There was Strontium 90 in the atmosphere,
But don't you let that get you down.....

You're still the only two headed baby in town!

FC