My wife refuses to allow a clothesline for the very reasons you mentioned. Well, that and she thinks it's low class. (I am just the messenger)
2) Homes are now air-conditioned, with filters, and children spend less time outside. Again, they are not being exposed to small amounts of environmental allergens early in life.
I agree. We open our windows whenever we can. But, when we built the house we have to pretty much prove it was air tight to the building inspector to get the permit.
......children spend less time outside.....
Many girls beyond the age of 12 virtually never go outside.