I have an interesting DNA "discovery", altho it's not my own. My friend, Linda, who does my nails, is Vietnamese-American. Her mother, Lynna, born in 1972, is the daughter of an unknown Vietnamese girl and an American soldier. As soon as she was born, she was given up for adoption, and was adopted by a nice lady in her 60's. Eventually, Lynna married a Vietnamese boy, and moved to America, where Linda was born, along with 3 brothers. Linda has always known that she is 1/4 American, but it was always a "sore spot" with her mom, so they never really talked about it much. Her mom had been rejected and ostracized in Vietnam, because she was part American.
Over time, Linda and I have talked about doing my family tree, and DNA etc, and she expressed some interest in finding out her heritage. But she knew that it would upset her mom, and she also knew that she could not keep a secret if she knew, so she wrote it off. But she planted the DNA "seed" with her mom, and it eventually took root. about 6 months ago, Lynna told Linda that if she really wanted to do a DNA test to find out, she would be OK with it.
So Linda spit in the tube, and we sent it to Ancestry. Before too long, we had the results and she started getting matches. Almost immediately, we had a match for a 2nd cousin. So I wrote to the "match", who turned out to be a really nice and "receptive" woman, and who helped us sort out her tree to figure out who the "culprit" was. It turned out to be her mom's older brother, who had lived a rough life and had died just a month or 2 before we found him. That was a disappointment, but at least she knows his name, and that's more than she knew before. I was really shocked at the short length of time it took to identify him. That 2nd cousin match was really the key in making that connection.