ostensibly it's for the kids' good. but what happens in the end is that you have to be rich to pass all those tests and screenings.
maybe in some cynical way
that is the purpose - to see that the prospective parents have enough money
and like Ian said, what happens then is that people adopt children from 3rd world countries, and that's where it gets murky...shady adoption agencies/brokers, black-market trading of babies etc.
it's a sad world.
One Ring to rule them all, One Ring to find them,
One Ring to bring them all and in the darkness bind them
In the land of Mordor, where the Shadows lie
-- JRRT
M.C. Escher - Reptilien