The Case of Identical Twins
Let’s say there are two families, the Joneses and the Smiths. The Jones boys are identical twins; they share virtually 100 percent of their DNA. The Smith girls are just sisters; they share 50 percent of their genes. If DNA had
nothing
to do with the children’s spirituality, their religious intensity would be determined only by their upbringing and the events that happened to them—a run-in with a particularly vicious nun in Catholic school (which turns one person against faith), or an inspiring Pentecostal service (which turns another on to it).
If, on the other hand, genes
do
play a role, then you would expect to see the spiritual inclinations of the Jones boys matching each other more closely than do those of the Smith girls, because the Jones boys share twice as much of their genetic makeup. It doesn’t work to test this on an individual scale, but when scientists persuaded hundreds or thousands of twins to participate in a study, a clear trend did emerge. In study after study, researchers found that between 37 and 50 percent of the variation in spirituality appears to be explained by genes.
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To tease out the contribution of upbringing and life events (nurture) from one’s genetic wiring (nature), scientists have looked at a tiny subset of identical twins: those separated at birth. For those twins, environment (or nurture) cannot influence the siblings to be more like each other, since they were raised in different families and did not share the same environment.
Unfortunately for me, twin researchers didn’t include a category in their database for “identical twins separated at birth with strikingly similar spiritual intensity.” But fortunately for me, Nancy Segal, who heads the Twins Studies Center at California State University, Fullerton, happened to know Debbie Mehlman and Sharon Poset.
In 1952, when they were one week old, the twin sisters left a New Jersey hospital with different adopted families. For more than four decades, neither one knew that a genetic carbon copy existed somewhere in the world.
Debbie’s family moved to Connecticut, where she married and lives today. Sharon eventually moved to Kentucky. Only when they were forty-five years old did Debbie’s adoptive mother reveal that she had an identical twin.
In retrospect, it made sense, Debbie told me. “We both always felt there was something missing.”
Debbie hired a private investigator, and two months later, she and her sister, Sharon, met at the airport in Hartford. Coincidentally, the two had selected black skirts and beige tops for their meeting. Their accents fell into an identical New Jersey twang. Each had an odd habit of crossing her eyes to suggest irony.
“We did so many things alike, people were clutching their chests,” Sharon recalled.
As they pieced their stories together, they realized they shared a number of twists in life: from similar haircuts throughout their teens (not so interesting), to majoring in sociology (a little more intriguing), to raising one child each, both of whom joined AmeriCorps. But it was their spiritual journey that drew my attention. Debbie was Jewish, Sharon was an evangelical Christian, and both had always been drawn to God.
Sharon grew up Catholic; her parents and her other (nonbiological) sister displayed little enthusiasm for the faith.
“The sister I grew up with would go to church and wait in the parking lot and grab a bulletin so my parents would think she had gone to church,” Sharon recalled.“But I always wanted to go to church. I got my Holy Communion. I was fascinated with it.”
Eventually, Sharon became a born-again Christian, and she now works at an 8,000-member “megachurch.” Like Debbie—who teaches in her synagogue and is learning Hebrew—her faith is the center and circumference of her life.
Debbie, too, wondered about her early religious faith.
“I have a mother who’s like,‘Oh, I had a headache once during Yom Kippur so I never fast.’And that drove me nuts as a kid!” Debbie laughed.
As in Sharon’s case, Debbie was mystified that her nonbiological sister showed little interest in synagogue.“My [nonbiological] sister and I grew up in the same house, and I used to think, How come it means something to me and it doesn’t mean anything to her?”
The answer, she believes, lies in their genes. “When we went to school in the sixties, everything was nurture,” Debbie said. “It was all ‘environment, environment, environment,’ and I used to figure, Oh, my mother must just be weird, I must be like my dad, and try to rationalize. And then Sharon and I met, and it’s like,Well, there goes environment out the window.”
I put the question to Nancy Segal: Is it
all
genes?
“Nothing is all genes,” Segal said, “but I think it’s genes to a large degree. The content is fashioned largely by the culture, but
how
they’re doing things,
how
they’re going about living their lives, is very similar. And that has to be something genetically influenced, because they were raised in different places.”
Once the twin researchers believed they had established a link between genes and spirituality, it was inevitable that geneticists would try to find which genes made for a Sigmund Freud and which ones led to Saint John of the Cross. This line of inquiry is in its infancy, with relatively few studies, in part because scientists find it easier to win grants to study schizophrenia than spirituality. When the spirituality studies are conducted, it is usually on the sly, with data gleaned from existing smoking or alcohol-abuse studies. This is how Dean Hamer claimed he stumbled—oh so controversially—upon the “God gene.”
The God Gene at NIH
If you want to conduct a spirituality test on very high-end subjects, look no further than Bethesda, Maryland. Dean Hamer and Francis Collins are both leading geneticists at the National Institutes of Health. They both love the scientific method. Where they part company is God; specifically, whether one’s inclination toward God boils down to genetic coding or something more.
“Genetics has become so much more powerful,” Dean Hamer told me. Hamer is a Harvard Ph.D. who works at NIH’s National Cancer Institute. “Things that seemed utterly mysterious, like the pattern of dots on the wings of a butterfly, have now been reduced to individual genes acting at specific times during development. So the idea that something as complicated as ‘why people pray’ might be studied, has gone from a complete fantasy to something that scientists can think about in a serious way.”
Hamer is author of
The God Gene
,
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a book that has many scientists pulling out their hair in frustration, since they felt the study was shallow, sensational, and published without scrutiny by other scientists. I wasn’t sure what to expect when I arrived at his four-story brownstone near Logan Circle, a once scary, now fabulously expensive neighborhood in Washington, D.C. Hamer opened his door, shushing aside two barking dogs. He wore a black T-shirt, tan shorts, and Birkenstock sandals. He looked like a professional soccer player, trim and compact, with salt-and-pepper hair, neat features, and cocky eyes. He was a man that any woman, and some men, would notice at a cocktail party.
We walked up the spiral staircase to the third floor. A framed copy of the
Time
magazine cover featuring
The God Gene
hung on the wall. A dozen copies of his book were scattered on tables and chairs. We gravitated toward a tiny room of rich grays—gray walls, gray chairs, a small round glass table.
Hamer was a practiced interviewee—engaging, modest, with the charming verbal patter of a springtime shower. He has written that he is a “materialist,” which means he believes that much of people’s behavior can be reduced to physics and chemistry. What, then, drew him to look for God in the genes?
“When I was a young adolescent, I thought for a while that I might want to be a priest or a minister,” he laughed. “But that’s because I was such a troubled child and had such a huge case of attention deficit disorder that I just wanted some way to get out of all the trouble I was in at the time. So for me it was probably not so much a deep sense of spirituality as a deep curiosity, combined with a willingness to do stuff that you’re not really supposed to do in science. That’s why I studied the gay gene, that’s why I studied personality. These are things that normal scientists are afraid to do, and I’m just, like, Heck, why not?”
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“So you’re still that troublemaking adolescent,” I observed.
“I’m still that troublemaking adolescent. But now I do it with a DNA extraction kit and scientific tools.”
Hamer described his study, which he conducted on his own time, using data collected for his work as a cancer specialist at the National Institutes of Health. He recruited about a thousand people, whom he asked to give a DNA sample and fill out the Cloninger “self-transcendence” test, the same one I had sprung on my mother.
Once Hamer knew which people scored high on spirituality and which scored high on cool rationalism, he looked for variations in their DNA.
Hamer found that the most spiritual people had one small difference in their DNA that was not present in the less spiritual people. The variation was located in a gene called VMAT2, which regulates dopamine and serotonin, both chemicals that affect the way people perceive the world and the way they feel about it.
“Everybody has the so-called God gene, the VMAT2 gene,” Hamer said. “But they have very slightly different versions of it. So it’s like different flavors of ice cream, some people like chocolate, some people like vanilla. Some people have the more spiritual version of the VMAT2 gene, others have the less spiritual version.”
Did this gene alone account for all of the difference in spirituality between two people? No. Half of it? Wrong again. The discovery, it turns out, was somewhat more modest: VMAT2 accounted for less than one percent of the difference in spirituality between two people. It raises the temperature from, say, 45 to 46 degrees, not from freezing to the boiling point. In other words, this is not the DNA equivalent of the Almighty who fills heaven and earth. It’s more like Pan, or Persephone, or the Furies: one small gene in a pantheon of genes.
“Clearly this is not
the
gene that makes people spiritual,” Hamer conceded, adding that he regretted the title of his book (although that title has surely accounted for robust sales). “There probably is no single gene. It’s one of many different genes and factors that are involved. As a biochemist, I don’t expect to solve the mystery of spirituality with one genetic analysis. But I do hope that it will inspire other scientists to get involved in this area.”
I asked him if his research had influenced his view of God.
“When I started out, I was a typical scientist, completely skeptical of anything religious—you know, ‘the opiate of the masses.’ As I was researching the book, I made it a habit to do various spiritual or religious things. I went to religious services every Sunday. I spent a week in a Buddhist retreat in Japan, studying Zen. And the more I did this, the more I realized that, yeah, this really is a very powerful thing.
“But it hasn’t affected whether I think there’s a ‘God’ or not,” he continued.“I don’t see any compelling evidence that there is. I have no disproof, either, so I’m your classic agnostic.”
This rooting around for God in the genes reminded me of an acquaintance of mine, a neurosurgeon who loved carving tumors out of people’s brains. The surgery is so
interesting
, he would say to me, but he never mentioned whether the patient lived or died unless I asked him. As I talked to Hamer, I recognized the same sentiment: whether or not God exists didn’t really matter to him; he had no dog in that fight. I wanted to hear from a scientist who did.
More Than Molecules
Francis Collins and I sat in his spacious, sun-drenched office at NIH overlooking a canopy of trees. Collins headed the federal government’s Human Genome Project and wrote
The Language of God.
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He was a towering man with a tame mop of gray hair and large features that fell automatically into a smile. On this blistering-hot day he wore black jeans and a blue T-shirt with an American flag spanning his chest. It was the Friday afternoon before the July Fourth weekend in 2006. The employees had the afternoon off; most of his colleagues had left, but Collins talked with me for more than an hour.
“There is no gene for spirituality,” he told me. “There may be a lot of genes that play some role in the development of a personality” inclined toward God, he said, but “there are so many other things at work.”
Dean Hamer’s book evidently vexed him. Collins ticked off the flaws. Hamer had declined to publish the findings in a peer-reviewed journal, opting instead to go straight to the public with a popular book. That meant his research did not endure rigorous scientific review and challenge. Collins continued: The findings have not been replicated, meaning that the “spiritual” properties of the VMAT2 could be a statistical fluke. The entire project rested on self-reported questionnaires, he noted. And finally, he said, the “God gene” seemed to account for a tiny difference in self-transcendence.
“Maybe the right title for the book should have been:
The Identification of a Gene Variant Which,While Not Yet Subjected to a Replication Study, May Contribute About One Percent or Less of a Parameter Called Self-Transcendence on a Personality Test.
” Collins reflected on that a moment. “That probably wouldn’t sell many books, though.”
But isn’t Hamer on the right path? I asked. Genes have already been identified with diseases like Parkinson’s and Alzheimer’s. Why not a gene—or a cluster of genes—to explain spirituality?
“Spirituality is a very different phenomenon.We’re not talking about pathology here. We’re talking about a transcendent experience,” he argued. “You could no more identify a genetic glitch involved in spirituality than you could identify a genetic glitch in the experience of being alive. It is much too complicated and interwoven with every aspect of your personality, of your consciousness, of your sense of who you are, to be able to be pinned down in that very deterministic way.”