A pair of identical twins lived apart for 28 years after one off them was accidentally switched with another infant in the hospital nursery. Twin expert Nancy Segal details what happened next in Someone Else's Twin: The True Story of Babies Switched at Birth.
Lawrence Wright has just written the new book "Twins and What They Tell Us About Who We Are". It is published by Wiley. In his book, he explores how research on twins is helping us understand how genetics shapes our lives. Wright is a staff writer for the New Yorker. (Interview with Barbara Bogaev)