Someone Else's Twin

Someone Else's Twin

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by Nancy L. Segal

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The combination of a riveting true story and cutting-edge twin research makes this book an irresistible page-turner.

Identical twins Begoña and Delia were born thirty-eight years ago in Spain’s Canary Islands. Due to chaotic conditions at the hospital or simple human error, the unthinkable happened: Delia was unintentionally switched with


The combination of a riveting true story and cutting-edge twin research makes this book an irresistible page-turner.

Identical twins Begoña and Delia were born thirty-eight years ago in Spain’s Canary Islands. Due to chaotic conditions at the hospital or simple human error, the unthinkable happened: Delia was unintentionally switched with another infant in the baby nursery. This fascinating story describes in vivid detail the consequences of this unintentional separation of identical twin sisters. The author considers not only the effects on these particular sisters, but the important implications of this and similar cases for questions concerning identity, familial bonds, nature-nurture, and the law.

Editorial Reviews

Long-lost siblings have been the subject of numerous novels and films, but real-life stories of such separations possess infinitely more poignancy than any contrivance. Nancy L. Segal's Someone Else's Twin explores surprisingly frequent cases of maternity ward mix-ups and their fascinating long-term consequences. She focuses particularly on separated-at-birth identical twins on what their development tells us about nature vs. nurture, sibling closeness, and personality traits. A fascinating probe of foundlings gone awry.

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Prometheus Books
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6.20(w) x 9.10(h) x 1.20(d)

Read an Excerpt


The True Story of Babies Switched at Birth
By Nancy L. Segal

Prometheus Books

Copyright © 2011 Nancy L. Segal
All right reserved.

ISBN: 978-1-61614-437-1

Chapter One

INTRODUCTION Discovery in Las Palmas

Every once in a while a researcher discovers a problem, event, or situation that is irresistible, something so compelling that she drops everything to study it. This happened to me in June 2008 when I learned about Delia and Begoña, a pair of switched-at-birth identical twins from Spain's Canary Islands (Islas Canarias), located off the Moroccan coast. In 1973, newborn twin Delia, born on January 18, was accidentally switched with unrelated infant Beatriz, born on January 15, in the crowded nursery of the Nuestra Señora del Pino Hospital. It is likely that the three infants were placed in the same incubator, making an exchange of babies likely by either of the two nurses in charge of sixty newborns. In that instant, Begoña and Beatriz became a fraternal "twin" pair, and Delia became a first-born "singleton" child raised by a family with whom she had no biological connection. No one discovered the mistake until 2001 when the twins and Beatriz turned twenty-eight, at which time two chance encounters, two incidents of mistaken identity, and more than a little curiosity finally revealed the truth.

Lawsuits filed against the Canary Islands Health Service by the twins and their families continued for years. The case drew little attention until 2008, when it was allegedly leaked to reporters in the capital city of Las Palmas on the island of Gran Canaria. News spread quickly through the seven islands comprising the Islas Canarias, across Spain, and throughout the world. Psychologist Payam Heidary from California sent me a link to the online story. Minutes after reading it I was riveted and knew I would go to Las Palmas to meet the twins, their families, and their attorneys. I wanted a closer look at the circumstances and consequences of this incredible case—my only fear was that another investigator would get there first. I learned that Delia and Begoña were only the sixth pair of switched-at-birth twins ever identified; I learned of a seventh pair shortly after I discovered them.

I was fortunate that the families' attorneys, Sebastian Socorro Perdomo (for Delia) and José Antonio Rodríguez Peregrina (for Begoña and Beatriz) gave me full access to their clients while they turned away most reporters, journalists, and other individuals seeking information about the twins. The lawyers reasoned that my professional background in twin research might help their case. I sent Socorro several articles about twins reared apart and a 2005 book chapter I had written about switched-at-birth twins before I arrived.

The Spanish press and other newspapers in mostly Latin countries began covering the twins' story in 2008. In June of that year Socorro's office arranged for me to be interviewed by Monica López Ferrado, a science reporter from Spain's leading national newspaper El Pais. I received Ferrado's e-mail message while changing planes in Dallas en route to Louisville, Kentucky, for the annual Behavior Genetics Association meeting. Ferrado produced what must be the best, most comprehensive newspaper coverage of this case outside Gran Canaria. When I arrived in Las Palmas in September 2009, I was interviewed by Antonio F. de la Gándara, a writer from the local Canarian newspaper Canarias 7, who also covered the case extensively.

I traveled to Las Palmas in September 2009 to spend twelve days gathering material. I stayed at the Tryp Iberia Hotel, just three kilometers (two miles) from the city's popular beach, Playa de las Canteras, and marveled at the hotel's gorgeous views of the ocean. Scenery aside, the hotel is also situated approximately midway between the two attorneys' offices, located, respectively, in the old town of Triana Vegueta (Socorro) and the newer development along Calle Luis Doreste Silva (Peregrina). With much to be done, I had only one free weekday. I used it to visit the old Cathedral Santa Ana and Casa Colon (Columbus Museum) in the historic scenic section of Vegueta and to explore the bustling shopping promenade Calle Mayor de Triana (see figures 1.3 and 1.4).

Before I got to work, I wanted to understand a bit more about where the twins grew up. On Calle Alcalde José Ramirez Bethencourt, not far from the hotel entrance, is a statue of a large canine, shown in figure 1.5. Most people assume that the seven Canary Islands were named after the bird, the canary, but the islands were instead named after the dogs that figured significantly in their history. Canary birds were, in fact, later named after the islands to which they are native. There are many historical references to dogs on these islands and many different stories about how the Canary Islands were named. Archeological excavations on one of the islands, Tenerife, showed that dogs were buried with their masters to lead their souls to the place of the dead. As for the name, it may derive from the North African tribe the Canarii who once inhabited the island of Gran Canaria, the twins' birthplace. The name might also come from the Latin term Insular Canaria, which means Canary Island. Whatever the reason, eventually people began calling the islands the Islands of Canaria, then the Canary Islands.

I do not speak Spanish, so I worked closely with interpreter Jessica Crespo. She accompanied me to the attorneys' offices, the twins' homes, the judge's office, the shopping mall where the twins first met, and many other locations. I found Jessica through the American School in Las Palmas, where she teaches English. I hired Jessica based largely on her credentials—she holds a bachelor's degree in translation and interpreting with a major in law and economics and a master's degree in audiovisual translation from the University of Las Palmas. Jessica is also a sworn translator, as named by the Ministry of Foreign Affairs, and has studied children's literature translation at the University of Surrey in England. She showed an impressive command of English, evident to me during telephone interviews prior to my leaving for Spain. I met Jessica in person on September 13, the day before our interviews with the twins began. Jessica was a stunning, twenty-seven-year-old woman who spoke French as well as English and Spanish. She had shoulder-length brown hair and brown eyes and stood taller than her five-foot, eight-inch height because of the shoes she wore. I was lucky to have found Jessica because her wonderful social skills put the twins and their families at ease during the interviews, and we became friends as well as colleagues. Jessica is pictured in figure 1.6.

The result of my research in the Canary Islands is this book, Someone Else's Twin, in which I examine and describe the traumatic life changes with which Delia, Begoña, and Beatriz still grapple. I also introduce other switched-at-birth twins and singletons whose life stories were similarly altered beyond recognition. This book is also about the significance of the families' experiences for women having babies, parents raising children, lawyers protecting justice, and researchers studying behavior. I chose the title Someone Else's Twin because it captures the switching of the twins from the perspectives of everyone involved.

For readers to understand my immediate response to news of the Canary Islands twins, I must go back in time. I am a fraternal twin. My sister Anne and I were the only children born to our parents Al and Esther Segal, both in their early thirties. The double conception was natural— my mom was just approaching the age at which the chance of having fraternal twins starts to rise. She had an easy pregnancy, although we were born prematurely at seven-and-a-half months, as are many multiple-birth infants. One could also say that we were an early reared-apart pair—Anne, the larger and more robust baby, went home after a few days' stay in the incubator, while I was a month-long incubator occupant.

Over the years, friends and relatives sent us the usual matching outfits, but they did not look adorable on us. I discovered several photographs taken when we were two, three, and four showing us in identical T-shirts, shorts, and dresses. Seeing them today gives me the impression of two kids trying to look like twins, making it easy to understand why my mother rarely dressed us alike. Our physical differences have persisted—since childhood, Anne stood four inches taller than me, so I often received her hand-me-downs. Anne's hair is short and wavy, while mine is long, straight, and slightly darker than hers. No one ever confused us or suspected that we were twins, although some people forget which name goes with which twin.

The differences between Anne and me extend beyond our looks. Anne is a corporate attorney; I am a psychology professor. Anne is slightly introverted; I am fairly extroverted. Anne is married; I am unmarried. Anne lives in New York; I live in California. But we are close sisters who trust each other more than any other person in the world and laugh together at jokes no one else would follow. However, it was our differences, not our similarities, that captivated me and caused me to think hard about how children growing up together can be so dissimilar. My dual interest in twins and psychology has defined my career, and I've had more fun than many of my colleagues trying to answer all sorts of human developmental questions. For me, twins bring human interest and personal relevance to a scientifically significant research subject. Their personal stories illuminate the test data in many ways. It is amusing to hear that identical twins independently choose similar outfits, buy the same birthday cards, or make the same unusual mistake on an exam. But these events are consistent with research showing that identical twins have similar tastes, preferences, and abilities.

There is another small piece to this story. Just for fun, Anne and I had our DNA tested at Affiliated Genetics, a Salt Lake City, Utah, laboratory that performs paternity and twin-typing (identical and fraternal) tests. The staff distributes special kits that allow clients to prepare saliva samples at home and mail them to the laboratory for processing. I often use their services for determining whether twins in my studies are identical or fraternal.

Our results were perfectly reasonable, but gave me a slight jolt. Anne and I had fewer than the average eight out of fifteen matches expected for fraternal twins and full siblings. The results are certainly consistent with genetic relatedness. In fact, it is possible for fraternal twins and full siblings (both of whom share half their genes, on average, by descent) to differ on all tested DNA markers because they have only a 50 percent chance of inheriting each gene in common. Because I knew this in advance, my momentary concern quickly subsided. Delia, Begoña, and Beatriz's case has heightened my awareness of how previously unknown birth events can so profoundly alter lives years later.

Knowing who your relatives are is a fundamental part of personal identity and developmental continuity, as the switched-at-birth twins have clearly shown. What happened to the Canary Islands families could happen to anyone.


Scientists see twins as natural experiments that reveal how and to what degree genes and environments shape human behavioral and physical traits. This natural experiment derives from the availability of two types of twins, monozygotic (identical or MZ) and dizygotic (fraternal or DZ). MZ twins originate from the splitting of a single fertilized egg or zygote within the first two weeks after conception. Most textbooks state that MZ twins share 100 percent of their genes, and that is theoretically correct. However, errors in cell division, mutations, copy number variations (presence of more than two copies of some genes), differential X chromosome inactivation in MZ female twins, and other events make MZ twins not strictly identical. Still, MZ twins are as close as possible to natural human clones. It is generally believed that MZ twinning is a random event, meaning that anyone is equally likely to conceive such a set. However, some studies have questioned this wisdom, suggesting that the predisposition for having MZ twins is genetically transmitted within certain families.

DZ twinning is genetically passed down within families. The specific genes involved are as of yet unknown, but some good candidates for these genes have been identified. The conventional wisdom is that DZ twinning "skips" generations, and while this can happen in some families, this type of transmission has never been scientifically confirmed. DZ twins result when a woman simultaneously releases two eggs that are fertilized by two separate sperm. As I explained above, DZ twins share 50 percent of their genes, on average, making them genetically equivalent to full siblings. DZ twins may be same-sex or opposite-sex, events that occur with approximately equal frequency. DZ twins occur more frequently among Black populations, followed by Caucasian populations and Asian populations in succession, further supporting the presence of genetic effects on nonidentical twinning. DZ twins are also born more frequently, on average, to women conceiving in their mid thirties and later and more frequently to women who are taller and heavier. Spontaneous DZ twinning has, in fact, been associated with increased maternal levels of follicle-stimulating hormone (FSH) found in relatively taller, heavier, and older women. The link between DZ twinning and maternal age partly explains recent changes in the frequency with which twins are born.

The twinning rate in the United States in 2008 (the latest year for which statistics are available) and in other Western nations is about one in thirty births, a dramatic increase from the one in sixty births reported in 1980.14 This increase is primarily due to the availability of assisted reproductive technology (ART), which allow infertile couples to conceive. Among these couples are those who delay having children and thus experience difficulty conceiving. ART mostly elevates the chance of having fraternal twins, although in vitro fertilization (IVF or implantation of embryos in the uterus) has been associated with an unexpected increase in MZ twinning (albeit to a lesser degree), possibly due to manipulation of the zygote in the laboratory.

Classic twin studies involve comparing behavioral and physical similarities between MZ and DZ twin pairs reared together (MZT and DZT). This simple and elegant technique was first described in 1875 by the British scholar Sir Francis Galton. Galton's work preceded scientific knowledge about the biological bases of twinning, yet he reasoned that twins who looked alike shared all their heredity while those who looked different shared only a portion of their heredity. By comparing the life histories of thirty-five twin pairs in which "similarity at first was close" and twenty twin pairs in which there was "great dissimilarity at first," Galton concluded, "It is, that their history affords means of distinguishing between the effects of tendencies received at birth, and of those that were imposed by the circumstances of their after lives; in other words, between the effects of nature and nurture."

A wealth of twin research has since shown that MZ twins are more alike than DZ twins in height, weight, intelligence, personality, athleticism, social attitudes, job satisfaction, and medical conditions, demonstrating genetic influence on these traits. Virtually all measured human characteristics show some degree of genetic influence.

Another powerful way to study twins involves comparing the behaviors of MZ and DZ twins reared in separate families (MZA and DZA, with A standing for "apart"). These rare pairs are extremely valuable research subjects because of their shared genes (100 percent and 50 percent on average, respectively) and their exposure to different influences within their respective families and communities. Growing up apart, without the influence of the other twin and without being subject to the same family circumstances, these twins offer scientists sensitive tests of the relative contributions of genes and environments to behavioral and physical traits. In fact, the MZA intraclass correlation (a statistic expressing the degree of twin resemblance that varies from–1.0 to 1.0) directly expresses just how much variation among people is explained by genetic factors.


Excerpted from SOMEONE ELSE'S TWIN by Nancy L. Segal Copyright © 2011 by Nancy L. Segal . Excerpted by permission of Prometheus Books. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

Meet the Author

Nancy L. Segal, PhD, is a professor in the department of psychology at California State University, Fullerton, and the director of the Twin Studies Center, which she founded in 1991. She is the author of Indivisible by Two: Lives of Extraordinary Twins; Entwined Lives: Twins and What They Tell Us about Human Behavior; and Born Together–Reared Apart: The Landmark Minnesota Twin Study. She is also the senior editor of Uniting Psychology and Biology: Integrative Perspectives on Human Development.

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Someone Else's Twin 5 out of 5 based on 0 ratings. 2 reviews.
HawkSF More than 1 year ago
Just when you thought you have heard all the baby mixup stories....this happens! Crazy!!
Anonymous More than 1 year ago
This is a good bonok about dora the exploer in her cool adventer and fart to everyone