GROUNDBREAKING '20/20' REPORT ON TWINS SECRETLY SEPARATED AT BIRTH, STUDIED FOR SCIENCE AND KEPT IN THE DARK ABOUT THE TRUTH UNTIL ADULTHOOD PROMPTS LONG-AWAITED APOLOGY

Hour Searches for Answers as to Who Was Involved in Shocking Experiment

'20/20: Secret Siblings' Airs Saturday, June 2 (10:00 - 11:00 p.m. EDT), on ABC

"20/20" features the reunion of Howard Burack and Doug Rausch, twins who didn't know they were separated until they were adults.

An unknown number of Americans reached adulthood without knowing and experiencing a fundamental part of their identity - that they have an identical twin. "20/20" features the stories of three of these people who made this astounding discovery, a shocking truth that was deliberately kept secret from them most of their lives. These twins were separated as infants, given up for adoption to different parents, and then monitored for a little known "nature vs. nurture" study - conducted completely in secret - by a preeminent psychiatrist. "20/20" and filmmaker Lori Shinseki, director of the documentary "The Twinning Reaction," have been on relentless hunts for answers as to who was responsible for disrupting the lives of these twins and robbing them of their true identities. "20/20" tries to find out just how many twins and triplets were separated, interviews people involved in the study and shares the reunion of a set of twins, now adults. The program includes updates to the original report that aired March 9, including an apology from the Jewish Board to the twins who appeared on "20/20." The Jewish Board controls access to the records from the study, which are under seal at Yale University. "20/20: Secret Siblings" airs Saturday, June 2 (10:00-11:00 p.m. EDT), on ABC.

Decades ago, a prominent New York City adoption agency separated at least five sets of twins and triplets, based on the recommendation of a psychiatrist, Dr. Viola Bernard. The agency never told the adoptive parents their child had an "other." Subsequently, under the guidance of another psychiatrist, Dr. Peter Neubauer, researchers tested, filmed and interviewed some of the children and families for years, under the pretense of conducting an "adoption study" without the knowledge or informed consent of the twins and their adoptive families. The data gathered by Dr. Neubauer is currently under seal and only the Jewish Board has the authority to release it. After the hour originally aired, the Jewish Board sent written apologies to the multiples who appeared on "20/20" saying, "... we realize that our efforts have fallen short and that we can and should do more ... we feel we must reach out, acknowledge our past error, and set a new moral course for the future." Some of the twins from the study have accepted the Jewish Board's invitation to start a dialogue to "... begin the task of repairing past wrongs and making them right."

"20/20" is anchored by David Muir and Amy Robach. David Sloan is senior executive producer.