Identical twins Delia and Begona were born thirty-seven years ago in Spain's Canary Islands. Due to chaotic conditions at the hospital or simple human error, Delia was unintentionally switched with another infant in the baby nursery.

In this fascinating story, Dr. Nancy L. Segal, herself a twin and an expert on twin research, describes the consequences of this unintentional separation of identical twin sisters. She considers not only the effects on these particular sisters, but the implications of this and similar cases for questions concerning identity, familial bonds, nature-nurture, and the law.

Delia and Begona grew up never knowing the truth about their birth, and their parents had no idea that an error had been made. When one twin was confused for the other by a friend during a chance encounter in a clothing store, the twins finally met at the age of twenty-eight. Once the startling discovery of the twins' actual identities was made, the families were in shock. The newly reunited sisters experienced mixed emotions and deep confusion, as did their parents, brothers, and sisters. Eventually, the case led to worldwide publicity and a lawsuit that lasted for years.

Based on her extensive research into the psychology of twins and interviews with family members, Dr. Segal explores many questions of universal human significance: How do mothers know who their biological children are? How much does our family contribute to our sense of self? Are we more like the people who raised us or the people we are born to? Can the legal system ever compensate parents for a mistake that really has no remedy?

Beyond the case of Delia and Begona, Dr. Segal discusses prior cases of twins and non-twins switched at birth. She also examines custodial decisions concerning children who are the result of donated sperm or eggs by individuals outside the rearing family. She further elucidates the benefits to children from adoption.

The combination of a riveting true story and cutting-edge twin research makes Someone Else's Twin an irresistible page-turner.