Identical Strangers
Not sure if this should go under Health or Social Issues, as it spans both, but as mental health is involved, I chose Health.
I watched a very interesting documentary last night about identical triplets who were split up at birth.
I'd heard about these guys about a year ago, but the programme explained a lot more.
Basically, in the early 60s, identical triplets were put up for adoption in New York. They were separated at birth, and placed with three families, none of whom were told of the existence of the other two triplets.
By chance, two of them met at age 19, in 1980, when one of them started at a college that another of them had previously attended, and everyone was saying Hi Eddy! to him, although he wasn't Eddy, because he looked just like him.
Anyway, the two met up, and when their case was publicised, a third triplet saw them in the paper, and so all three were reunited.
However, it turned out they they had been part of a psychology experiment, where they, and some pairs of identical twins had all been separated at birth, and placed with different families, to research whether nature or nurture was the dominant factor in personality, character traits, etc.
They then discovered that the families chosen were ones that had distinctly different parenting styles. These were known because all three families had already had a girl adopted from the same agency, and so the parenting styles were known.
The three were then monitored at intervals as they grew. The adoptive parents never knew the details of the research being done, and the monitoring sessions were passed off as something trivial.
So, none of the families knew that the boys were one of triplets, and never knew that they had been selected on the basis of parenting style and because they already had an adoptive daughter. They never knew that they were part of a long-running experiment into the Nature v. Nurture hypothesis.
I won't go into any more details, as you may want to watch the programme on catch-up. It was very well made, imo.
Obviously, the ethics of playing with lives in this way was called into question, and the effects that the realisations and discoveries had on the triplets are full of pathos.