A friend told me that an adult over the age of 35 cannot legally adopt in this country. She and her husband tried when it became apparent she could not safely conceive. She said that the only reason they were denied was because of their ages.
Other friends, working in the child welfare system, have told me that if a child reaches the age of 14 in this country without being adopted, they may as well forget it. It takes up to 3 years to go through the process.
These reasons are why American adults find it easier and quicker to undertake a foreign adoption -- just pay the fees, specify the kind of child you want, and then go get the child when he or she becomes available.
I am sure there is more more to it than that; but even so, it is a shameful thing that American bureaucrats have produced a system that makes foreign adoptions the preferred choice among Americans seeking to adopt.
It is no wonder that there are so many children in America who never get adopted, and who eventually age out of the child welfare system and end up on the streets.