Growing up, this man and his siblings were told by their parents that they actually had another brother and sister, but they passed away at childbirth. Decades later, the man took a DNA test from 23andMe just to learn that the brother and sister were, in fact, still alive and well.
Both siblings had been given up for adoption. The sister was the youngest of all of the children and the brother was the oldest. Both parents of the lost children had passed away so we will never know why two of the children were given up the adoption, and how the family didn’t catch the youngest one being given away.