My wife’s sister did the DNA testing two years ago. There was a hit in Seattle from 1971. It is my wife’s son that she gave up for adoption when she was 17.
The family grew by one and to call it a blessing for all concerned would be an understatement.
A couple of years ago I was able to help a distant cousin in Australia (adopted at birth) discover who her biological mother was. Her adoptive parents are deceased. She was conceived when her mother was raped (her biological father is deceased). The result was a very happy reunion. I knew about the cousin only because we both had taken DNA tests.