I suspect that William’s position as “co-youngest” in the family took him out of any real contention for inheriting resources such as the family farm, which ultimately went to Chelmo; therefore, William was not a threat to his older siblings. William was also a warm, generous, and studious child, making it easy to love him—his sibling conflicts were mostly with Wilber. In contrast, the wealthy Japanese brothers may have worried that a large portion of their parents’ assets would pass to their oldest brother, leaving them relatively empty-handed. Little information about the relationships among the Japanese siblings is available, but the enduring doubts of the youngest three and their intensive search for their biological brother suggest they were not close to their putative older sibling.
As an infant, youngster, and young teenager, William shared a bed with his mother, while Wilber, Edgar, and their father slept nearby. Ana cried when William left for the military, but she didn’t cry when Wilber joined four months later. It seems reasonable that her increased focus on William was connected to her knowledge of his poor health as a baby—the twin who was taken to Bogotá for treatment. However, mothers of extremely low birth-weight twins generally favor the healthier baby, who usually is the one who comes home first from the hospital.12 This could have been true early on, but as the years passed it was William’s sensitive nature and kind spirit that Ana found so endearing—although William may have actually been the healthier baby because he was born at thirty-five weeks, whereas Wilber was born much earlier, at twenty-eight weeks. William was also the twin preferred by Ana’s mother, Eva Castillo, who loved telling the story of how she brought him to Bogotá bundled in a blanket. Later, when William visited his childhood home, Eva doted on him. She died in about 2005 and never learned that the baby she brought to Bogotá was not the one who came back. Wilber felt no jealousy at his mother’s and grandmother’s preference for William, because Wilber believed he was his father’s favorite twin son.
Mothers have no reason to doubt that the babies they deliver are their genetic children, and maternal grandmothers have no reason to doubt that the babies their daughters deliver are their genetic grandchildren. The much longer history of having babies in intimate settings, rather than impersonal hospitals, explains why few question whether the baby handed to them is theirs, a postpartum response that has been preserved across generations. Thus the term maternity uncertainty is nowhere to be found in the scientific literature. Certainly, Ana Delina never suspected that she was raising someone else’s son—nor did Luz Marina, who was in exactly the same situation in Bogotá.
Ana and Carmelo: Breaking the Silence
Ana and her husband, Carmelo, were past seventy when these events unfolded. William, Wilber, and their four older siblings were justifiably worried that revealing what had happened would be such a big shock that their aging parents might be physically and emotionally overwhelmed. So William and Wilber crafted a plan to break the story gently and gradually to Ana and Carmelo. But in so doing they inadvertently raised their mother’s hopes that they had some good news to share.
William and Wilber agreed that they could best prepare their parents by casually tossing out suggestive questions and comments. This task, strung out over two weeks, was assigned to Alcira, their older sister, who enjoys a close relationship with their mother. In fact, Alcira was among the first to learn that her mother became pregnant for the seventh time and that a local natural medicine doctor had said she was having twins. She recalls that her mother didn’t believe the doctor until she delivered her twins after that tortured journey to the hospital in Vélez.
Ana may have been unaware that in developed countries older women, especially those aged thirty-five to thirty-nine, have a greater chance of conceiving fraternal twins than younger women. Releasing two eggs at once is actually a reproductive “error” because human females are built to carry just one baby. It is also true that as women approach the end of their reproductive years, their chances of conceiving a child with a genetic defect such as Down syndrome increase. Evolutionary psychologists have, therefore, speculated that some women’s bodies go through a kind of cost-benefit analysis—that is, bearing fraternal twins could be a final effort for them to transmit their genes to the next generation, but with the dual gambles of a high-risk pregnancy and delivery of one or two children with a genetic liability.13
Ana was about forty-five when she had her twins, an age by which twinning is on the decline, and her twins were identical, not fraternal, so another explanation is needed for why this older mother conceived an identical pair. Some scientists have wondered whether an aging egg might lack some nutritional and energy sources, leading to developmental delay and programming errors in the developing cells, creating identical twins in the process. It is also possible that, in older women, the membrane surrounding the early fertilized egg fractures, causing it to divide. I remember the reaction of a fortysomething mother whose identical twin daughters took part in one of my studies—she was in utter shock and disbelief at being pregnant, especially with twins. Studies in the United States and Israel have demonstrated that men past the age of forty, like Carmelo, are more likely to father twins than younger men, although the “older parent” effect for having multiple births is stronger in females.14 How older fathers contribute to twin conceptions is unknown, but could be partly linked to some men’s higher levels of an insulin growth factor called IGF-2, which is involved in cell growth and division; however, IGF-2 could affect twinning in both older and younger men, so there must be something more to this story. Many men like to think that their exceptional virility explains why their partner conceived two babies rather than one, but it’s just not so.
Alcira began by asking her mother how she would feel if one of her sons was not really hers. Since people had joked about this for years, Alcira’s remarks never aroused Ana’s suspicions—but she grew impatient with her daughter, whose questions seemed vague and insensitive. Instead, Ana was excited when William and Wilber invited her and Carmelo to Bogotá for an important visit—she was certain that Wilber was about to be married.
The days passed. Ana eventually learned that Wilber was not getting married—instead, the excuse was that she and Carmelo were needed in Bogotá to sign papers related to their son Israel’s death while he was in the military. Only one of her six children, Alcira, had married (and was widowed), so Ana was disappointed to learn Wilber was not engaged, but there were plenty of grandchildren. Alcira had six children, three boys and three girls. Chelmo had lived with two different women and fathered a boy with one and identical twin boys with the other. And Efrain had two daughters who lived with their different mothers.
* * *
The La Paz parents made the all-day journey to Bogotá several weeks after their children knew the truth. The family gathered in the modest apartment that William and Wilber shared over the butcher shop. Wilber had to work at the store, leaving to William the difficult task of telling his parents how he had been mistaken for someone who looks exactly like him and how the switch was discovered. It was easy for Wilber to walk away at this point—as the twin raised in the right place, he was angry but not emotionally distraught the way his brother was. And William was better suited to break the news gently and to assure his parents that he would always be their son. He was the boy she cherished for his kind, sweet manner.
Yet another odd twist had intervened in this already strange story—Ana already knew! Just minutes before she arrived at the apartment, someone in Bogotá told her the truth and swore Ana to secrecy—and Ana has never revealed the identity of this woman. More than once we asked her who it was, but Ana refused to say, leaving us to speculate. A likely candidate was Ana’s sister Edelmira, the twins’ aunt who had taken William back to La Paz a week after his grandmother had brought Carlos to Bogotá. Edelmira learned about the switch from one of her nieces. “I fixed my eyes on the baby—only it was the wrong one,” she said. An ambulance had carried Edelmira and the baby back to La Paz, but
the baby was concealed in blankets and tubes sprouted across his entire body, making him hard to see. Like everyone else, Edelmira was shocked and horrified by the news, but she never felt guilty because she had focused intensely on the baby each day and had immediately notified the nurse when his wristband was missing—that happened one afternoon at about 3:00 p.m., but it was in place when she returned the next day. Edelmira had read the baby’s tag on both days and they matched. Thus, it is likely that the switch happened before Edelmira first saw him.
Another potential whistle-blower was William’s godmother, Ana Liria, who nurtured William throughout this ordeal. Another was William and Wilber’s housemaid, Marlen Rodriguez, who cleaned their apartment and was privy to some private conversations—maids in Colombia are plentiful and inexpensive, even for people on limited budgets. But we will never know who told Ana. That may not matter now, although it may have mattered at the time. Learning life-changing news from someone outside the immediate family can be particularly devastating, because his or her intentions and motivations for doing so can be suspect. Alcira was furious that “it was not one of us.”
Ana was devastated when she first heard and wept hard. “Dear God, help me!” she cried. She worried that William, her favorite son, would abandon her and the rest of the family. She thought about the difficult life William had had, laboring long hours on the farm and never going to school because the family couldn’t afford to send him. Ana felt especially distraught at the knowledge that William would never meet his biological parents. And she worried about whether Carlos had been well cared for.
The news was also hard on Carmelo, who did hear it for the first time from William—suddenly his son by mistake—but Carmelo is much less expressive than Ana. The poor man was puzzled at first, thinking that Ana had delivered all four boys and two had been taken away! When we met Ana and Carmelo at their home six months later, Ana was still crying, unable to fully assimilate what had happened, but slowly gaining acceptance. Her somber mood was occasionally interrupted when her tough, hot-tempered Santanderean nature broke through, as when she insisted that the four brothers file a lawsuit against the Hospital Materno Infantil. A lawsuit made perfect sense to Ana, an idea she underlined by asking, “Do chickens crow?” This sarcastic touch matched the feisty nature of this small woman. But Ana also had a warm, sweet side that William and Wilber’s childhood friends told us about, and she was ready to show it whenever Carlos came around. Carmelo stood by silently, but his eyes were wet. By now he knew that William would always be his son, but months had passed and he still didn’t know whether Carlos ever could be. Still, he felt connected to the son he hardly knew.
Paternity Uncertainty: Who’s the Father?
In contrast to mothers and maternal grandparents, fathers and paternal grandparents have some reason to doubt their genetic relatedness to their children and grandchildren, giving rise to the term paternity uncertainty. That is because ovulation is hidden, fertilization is internal, and women can have sex at any time. Thus, males can never know for sure whether the child delivered by their partner is truly theirs. Paternity uncertainty is of considerable interest to evolutionary psychologists—it is well known that mothers generally invest more time and care in their children than fathers do and that fathers may invest more in some children than in others. The different levels of investment fathers extend to each of their children results from many factors, but one may be their certainty of relatedness to a given child.15 Perhaps Carmelo’s preference for Wilber was partly tied to the familiar features he recognized in this son.
Jorge and Carlos: “Our Family Has Grown”
Jorge and Carlos had to tell their aunts—their mother’s five sisters—what had happened. All the aunts had been with the boys for birthdays, baptisms, graduations, and other significant events in their young lives. Two, Blanca Cecilia and Maria Teresa, were like their second mothers, having lived with them for nineteen years in their two-story home. Even the sisters who had married and raised families of their own—Leonor, Maria Esther, and Ana Rosa—were closely involved.
Although he was reluctant at first to act on the evidence Jorge had shown him, Carlos took the lead. He called Leonor and Maria Esther and invited them to lunch. The occasion, he said, was that “the family had grown.” Leonor, cool, elegant, and interested, assumed that “Carlito’s” girlfriend was pregnant, but he promised her that was not the case. He told her to just come to lunch.
When Leonor and Maria Esther arrived at the restaurant, Carlos showed them the photographs and described the probable mix-up at the hospital. His aunts were stunned—they had known their nephews all their lives, and nothing like this had ever come up, in their family or in anyone else’s. The two aunts adored Carlos and Jorge, both so well behaved, studious, and professional. The aunts knew that their sister Luz had brought the boys up well and that neither one had been in serious trouble at school or in the neighborhood, unlike some of their peers. Like everyone who knew Jorge and Carlos, Leonor and Maria Esther recognized the huge personality and physical differences between the twins, but they never suspected that anything was amiss because fraternal twins can differ by quite a lot—their sisters Blanca Cecilia and Maria Esther were fraternal twins, and they were quite different. Leonor and Maria Esther eventually laughed to brighten things up, and announced that they had just gained two nephews.
Carlos’s mood that day was a mixture of unease and apprehension. Leonor assured Carlos that God does things his way. She believed that her sister Luz Marina would have been sad but accepting of what had happened. In the end Leonor stopped laughing and left her favorite fish dish untouched.
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Because she had helped raise Jorge and Carlos since birth, Blanca Cecilia identified as a kind of mother, but her feelings of affection may have also reflected her own status as a fraternal twin, a relationship that her nephews believed they shared until recently. Most twins develop a quick rapport with other twins because they recognize that they have something fundamental in common, although the attraction is greatest when the twin types are the same. Twins run fairly rampant on the maternal side of the brothers’ family. Luz was born a twin, but her twin sister died shortly after birth, so whether she was an identical or fraternal twin is unknown. Luz walked with a limp, supposedly because of her own mother’s difficult multiple birth delivery. Twin boys also appeared in the next generation, delivered not just by Luz but also by Blanca Cecilia’s twin, the brothers’ aunt Maria Esther, although one of these twins also died soon after birth. Birth information was unavailable for the paternal side of the family.
Twins run differently in the La Paz family, but they are plentiful there too. The grandmother who brought the baby to Bogotá did not deliver twins, but one of her five children delivered fraternal twin sons when she was nineteen—Edelmira, the aunt who brought the wrong baby back to La Paz. Mothers of twins are exquisitely sensitive to twin development and twin relationships, so while the exchange was not her fault, Edelmira’s role in the mistake was difficult for her to bear. Another of Ana’s sisters delivered male twins when she was about seventeen, but both died shortly after birth. Ana delivered identical twins, and one of her sons fathered identical twin boys.
All the mothers in both families had conceived their twins without medical help. However, assisted reproductive technology (ART), the medical procedure that produced the first “test tube” baby in England in 1978, is largely responsible for the dramatic rise in mostly fraternal twins in Western nations.16 Twins now occur in about one in thirty births in the United States, compared to one in sixty in 1980, and about one-third result from fertility treatments.17 Several procedures are now available. In vitro fertilization (IVF) combines an egg with a sperm in a laboratory dish, then implants the embryo in a woman’s uterus after a few days. Or sometimes a sperm is injected directly into an egg, a procedure known as intracytoplasmic sperm injection (ICSI). One or more fertilized eggs can then be implanted into the uterus.
Fer
tility treatments are not the only reason for the rise in twinning rates. The peak period for conceiving fraternal twins is when women are in their midthirties, and women are now having children at older ages. By delaying conception women run the risk of simultaneously releasing two eggs, which would produce fraternal twins if fertilized by two separate sperm. But other factors also affect the chances of conceiving fraternal twins, such as being a taller and heavier mother, engaging in frequent sexual intercourse—especially after periods of abstinence—being of African descent, and having a family history of twinning. The causes of identical twinning are less well known, but they do seem to run in some families, suggesting a genetic link.18
Who has twins and why leads to fascinating debates in the medical world and entertaining stories everywhere. I know a woman who naturally conceived quadruplets—two sets of identical twin boys—and thinks her two fertilized eggs divided because she had been baling hay for hours in extremely hot weather. Some residents of the “Street of Twins” in Havana, Cuba, claim that the fruit of the siguaraya tree is responsible for the twelve twin sets (both identical and fraternal) that live on their two-block strip.19 These stories engage our imagination, but they do not inform our understanding. Luz’s mother, Leonor Chavez, was thirty-eight when she delivered her fraternal twins, Blanca Cecilia and Maria Esther, and forty when she delivered Luz and her sister, whose twin type is unknown. Luz herself was thirty-six when she had her twin sons, Jorge and William—the perfect age for a fraternal pair—but her twins were identical. The La Paz family also shows a mix of identical twins, fraternal twins, and deceased twins. Chelmo’s partner, Martha Castañeda, and Ana’s sisters, Edelmira and Maria Eva, were young when they delivered their twins, somewhat increasing the chance of identical twinning—although Edelmira’s twin sons appear to be fraternal according to family members.20 Based on their identical appearance Martha did in fact deliver identical boys, but she was not a blood relative; the type of twins Maria Eva delivered is unknown. However, Ana was forty-five when she delivered her identical twin sons, Wilber and Carlos—she was not at high risk for bearing identical twins and had passed the peak period for conceiving fraternal twins. Her birth history adds to the mystery and wonder of human twinning, keeping us captivated and hungry for more information. Meanwhile, another expert was Blanca Cecilia, who believed she had predicted the switch.
Accidental Brothers Page 14