[Varda]

"I think I read that kids who grow up on farms has lots less asthma than city kids."

Years ago asthma was considered and mostly a first world disease. Poor kids who didn't spend time indoors except to sleep didn't get it. It correlated with something a horse trainer told me, horses raised shut up in heated and air-conditioned barns got heaves and those in open ended barns didn't.

[caseinpoint]

There's something to be said for small doses of contaminants which might build up immunities. At least that's what I told myself when my house wasn't antiseptic and the kids were crawling all over, putting things in their mouths. ;o)