Trying to figure out what makes twins tick may help us understand our own relationships.
There's a twin way of looking at the tragedy of Ladan and Laleh Bijani, the Iranian conjoined twins who died this week trying to become individuals.
"Twins sort of think of themselves as having three identities," says Nancy Segal, a fraternal twin and director of the Twin Studies Center at California State University, Fullerton. "They each have their own identities, and one they share."
It's that "third self" - an overpowering conjoining of feelings and emotions somewhere just short of ESP - that drives and sways most twin relationships.
My identical twin and I have been both nourished and depleted by it. Once we wanted desperately to be separated. Until we were.
By so many measures, the 29-year-old Bijani twins, who died during separation surgery in Singapore, had a full life together. They were beloved in Iran, even trotted out by the Ayatollah Ruhollah Khomeini after his 1979 Islamic revolution. They had both completed law school. They deeply loved one another. They had made extraordinary emotional adjustments. It may have been that, as two, they were far more powerful than either could have been as one.
Yet they chose a surgical alternative that many of their loved ones and many doctors believed was suicidal: an attempt to disconnect their conjoined skulls even though their brains shared common veins. Most twins who try it die, or are left brain-damaged. Before they found the surgical team in Singapore, other surgeons had refused them. In their words, the operation constituted separation "at all costs."
The two private women never fully articulated what motivated them. The answer may be as simple as a family videotape taken when they were girls. It shows one riding a bicycle, the other running alongside.
Who could want to live like that?
Debra Ganz, who runs a Twins Restaurant in New York City with her identical twin Lisa (all the employees are twins; if a waiter is fired, his twin is, too), tries to contemplate being physically conjoined to her sister.
"We'd have stabbed each other with our forks," she says. Yet so bonded are they that as children, "if our parents left us home together, we each felt home alone. If they left another sister with us, we weren't alone."
The Bijani twins' reason for wanting to separate may be a thoroughly universal one, the reason why twin relationships fascinate medical researchers, why twin-related studies are believed key to understanding countless mundane aspects of the human condition: television watching, happiness, virginity, intelligence, Tourette's syndrome, suicide, criminal behavior, anorexia, cigarette smoking, Alzheimer's, religious values, divorce, alcoholism, homosexuality, mental illness.
Understanding twin relationships helps us understand "why we're happy, why we're sad, why we're tolerant or temperamental, why we love the way that we do," says researcher Segal, whose 1999 book Entwined Lives: Twins and What They Tell Us About Human Behavior is considered the standard reference in twin research.
"Identical twins may come closer than anyone else to achieving the coordinated, harmonious relations for which we all strive. ... Conjoined twins uniquely capture the conflict between our desires for intimacy and freedom."
As boys, my brother and I were called "Jimjohn." Our dad bought us one bicycle for our birthday. When we were 12, Jim stood up to the toughest bully in our eighth-grade class. It's a famous family story. Jim told him that the next time he saw him, he would "kick his a--." When the bully finally caught up to us in private, he beat up both of us. Separately. We each waited our turn. We hated being twins.
The Bijani twins were both named after the Farsi names for flowers. When they were eight, they tried to separate by walking away from each other, but the pain made them both cry.
"Actually, we are opposites," Laleh told reporters in Singapore.
Laleh was the quiet one. She liked books and newspapers and wanted to be a journalist. She liked to chat on the Internet, read the Koran and pray. She loved animals.
Ladan hated animals. She did the cooking and cleaning. She was the extrovert, the one who usually faced photographers. She wanted to be a lawyer.
Her dream won out. After Iran university officials realized there was no way for them to compete individually on college entrance exams (they whispered answers to each other) they granted them a joint scholarship to study law at Tehran University. It took them 61/2 years to finish. At the end, Laleh still wanted to be a journalist.
"These girls weren't stupid," says Dr. Louis Keith, a twin researcher and professor of obstetrics and gynecology at Northwestern University in Chicago. (Keith also is an identical twin. He refused to talk to reporters until I told him I'm a twin.) "What the Bijani twins may have been saying is, "We are tired of living a life that cannot be considered normal by any way shape or form. Sometimes it would be better not to live than to live with the daily misery of knowing we are freaks in the eyes of the world."'
Could Keith ever achieve total independence from his twin brother? "Nonsense! I'll never be independent," he says. "The idea of wanting to be completely separated has never crossed my mind."
But Segal believes conjoined twins tend to have stronger yearnings for independence than other identical twins.
"While most identical twins get along well, many conjoined twins are masters at negotiation, cooperation and compromise," she writes in Entwined Lives. "At the same time, their separate brains allow psychological separateness and selfhood, feelings crucial to all humans. ... I suspect physical connection intensifies identical twins needs to distinguish between themselves."
In 1975, Jim left Florida to join the Peace Corps. I stayed to be a newspaper reporter. I was temporarily paralyzed below the waist in a motorcycle accident while he was gone. When he came back, I hadn't done any physical therapy and weighed only 120 pounds. I could barely walk. He drove me to a Kmart and helped me buy a 110-pound weight set. A year later, I had gained 30 pounds and worn holes in the carpet from lifting and dropping weights. I wanted nothing more than to look like my twin again.
The deaths of Laleh and Ladan struck identical twins Craig and Mark Sanders differently.
They operate a Web site, Twinstuff.com. They went to UCLA together. They live next to each other in Houston. They throw a "Texas Twin Roundup" every October. They are married to identical twins, Diane and Darlene, and proposed to their wives in the same Orlando hotel room at the same time, sharing the same flowers and soft music. Craig has identical twin sons, who just turned 2. (It was just luck: There's no identifiable gene attributed for identical twins.)
The Bijani twins' tragedy caused Craig to contemplate his own twinness.
"There isn't that much that separates any identical twin from being conjoined. All identical twins start as conjoined, then separate in early stages of pregnancy. One out of every 220 sets ends up conjoined. Just knowing that, I look at the Bijani twins and believe that except for grace of God that could have been my brother and myself."
Craig is what they both call the "dominant" twin. He was born four minutes ahead of Mark. He tends to be the decisionmaker.
So Mark looks at the Bijani twins' tragedy from the perspective of a bossed twin. "Maybe I have a different theory," Mark says. "It seemed like one (Ladan) always answered the questions (about their decision to have the surgery). That's what struck me. It seemed like one was making all the decisions."
Did bossy Ladan compel timid Laleh to have the high-risk surgery? The twins never said that. They said only that they wished to see each other without mirrors. No one will ever know.
When Jim got divorced in Virginia, he and his wife fought bitterly over custody of their two small children. For one crazy, desperate moment, Jim considered kidnapping his own children and hiding them in my apartment in Florida. A lawyer told him to forget it. "Where's the first place they'd look for you?" he told Jim.
There's so much no one will ever know about what makes twins tick.
Segal was part of the famous Minnesota Study of Twins Reared Apart led by twin researcher Thomas Bouchard at the University of Minnesota.
The study was instigated by Bouchard's discovery of the "Jim Twins," Jim Springer and Jim Lewis, who were separated at birth and reunited in 1979 at age 39.
This is what researchers found about the Jim Twins, as documented in Entwined Lives:
Each Jim married twice. Their first wives were named Linda, and their second wives were named Betty.
Each Jim had a son with the same name but spelled differently: James Alan and James Allan.
As children, each Jim had a dog named Toy.
Both Jims took family Florida vacations in Pass-a-Grille in light blue Chevrolets without ever meeting.
Both Jims worked part-time as sheriffs.
Both Jims smoked Salems and drank Miller Lite.
Both left love notes to their wives around the house.
How can that be explained?
The best answer science can come up with is an unsatisfying, genetic one.
There's no gene that causes someone to hanker for Miller Lite and Salems, Segal says. But the same "complex gene combinations" in identical twins can trigger extraordinarily similar likes and dislikes.
But so much mystery remains.
"Regarding twin bonding, we will probably never have a complete understanding about anything," Bouchard said by e-mail. "(Physicist and educator) Freeman Dyson once argued that everything is infinite in all directions. I agree. Our theories about the very large (the universe) the very small (quarks, etc.) and the mind will always be approximations and never complete."
- Times researcher Kitty Bennett contributed to this report.Twin facts
IDENTICAL TWINS result when a single fertilized egg splits after conception. The resulting twins are the same sex and 100 percent genetically alike, though they have different fingerprints.
FRATERNAL TWINS result when two eggs are released at the same time and each egg is fertilized by a different sperm. Fraternal twins can be of the same or opposite sex. They share up to 50 percent of their genes, and are no more alike or different than any two siblings would be.
CONJOINED TWINS occur when a single egg, for unknown reasons, fails to divide fully into identical twins. Conjoined twins occur as often as once in every 40,000 births but only once in every 200,000 live births. About 500 such babies are known to have survived their first year, and fewer than a dozen are living in the United States today.
121,246 TWINS were delivered in the United States in 2001. That's about 30 for each 1,000 births. That rate has increased over the years. In 1990, the rate was 22.6 per 1,000; in 1980, it was 18.9 per 1,000.
TWINNING IS not related to genetics. Identical twins do not run in families. Only the age of the mother correlates with twinning: The older the mother, the greater the likelihood of having twins.
AN UNEXPLAINED SEASONALITY of twinning exists in some cultures. In Japan, for instance, (a nation that has among the lowest percentage of twins of any country), there's a dramatic increase in twin births during July, August and October.
- Sources: Centers for Disease Control and Prevention, USA Today, Department of Biology, Swarthmore College, Twinstuff.com and Entwined Lives: Twins and What They Tell Us About Human Behavior, by Nancy L. Segal.