IF you unwittingly pass through Twinsburg, Ohio, a Midwestern town in the United States on the first weekend in August, you might think you’ve stumbled into a mirrored funhouse.

Twins Days is an annual festival that brings thousands of twins from around the globe to northeastern Ohio to celebrate their twin-ness. The festival bills itself as the largest annual gathering of twins in the world.

It’s also one big petri dish for scientists, who flock to the festival every summer to study twins’ genetics and behavioral differences.

“It’s a club you can’t buy your way into,” said Katie Barry, 32, of New York City, who has been coming to Twins Days with her twin sister Kristy every year since they were 7. She gazes around at the carnival of costumed couples with a smile, searching for the right words.

“It’s this oasis of twin love.”

‘Where’s your twin?’

It’s almost too perfect that Twins Days is held in Twinsburg. The Cleveland suburb is named for identical twin brothers who helped settle the town and died of the same ailment in 1827, within hours of each other.

The festival got off to a quiet start in 1976, when 36 sets of twins showed up. It grew fast. This year, the event attracted more than 1,900 sets of twins, along with a smattering of triplets and at least one set of quadruplets. They came from almost every U.S. state and from as far away as Australia.

The event had a county fair feel and includes a parade, look-alike contests, a talent show and an enormous group photo — a human blanket of twins — taken in a field from atop a crane.

Twin humor was abundant. Siblings strolled the grounds in T-shirts that said, “Thing 1” and “Thing 2,” “The Good Twin” and “The Evil Twin,” or “I’m not Steven” and “I’m not David.”

More than a few had rhyming names, like Bernice and Vernice, Carolyn and Sharolyn and Jeynaeha and Jeyvaeha.

It may be the only place where you could stroll into a hotel and be asked by a staffer, “Where’s your twin?”

Twins said they enjoy profound bonds that few “singletons” — as non-twins are called here — fully understand.

An exclusive club

Identical twins are an even more exclusive club — roughly three in every 1,000 births.

They are formed when a single fertilized egg splits in two after conception, creating two embryos with the same genetic makeup and DNA.

Scientists love to study them because they help answer the age-old question about nature vs. nurture. Because identical twins share the same genes, any differences between them — say, more wrinkled versus less wrinkled skin — must be the result of their environment.

Take Laura and Linda Seber, 41, from Sheffield, Ohio for example.

The pair tied for eighth in their high school class of 404 students, attended the same grad school.

“If we’re genetically identical, I should be able to do everything that she does,” said Linda. “But sometimes it’s difficult being compared to each other. Because if I can’t achieve what she achieves, it’s like … why? Why can’t I do that?”

Indeed, it is hard to underestimate the mysterious psychic forces that bind one twin to another.

Don and Dave Wolf, 59, have identical graying beards that hang halfway down their chests. The identical twins live in Fenton, Michigan, and do long-haul trucking, sharing turns at the wheel during marathon cross-country drives.

The pair recall waking up one morning as boys, aged 11 or 12, to discover they had just had the same dream. A few years later, Dave suddenly became overwhelmed with concern for his brother only to learn from their dad that Dave had just broken his collarbone in a motorbike crash.

In the name of science

In a long white tent on the festival grounds, a long row of twins sat at tables before trays of color-coded food flavors: milk, potato chips and artificial sweeteners. Wearing nose clips to mask aromas, they uncapped each sample, took a taste and then spat into a plastic cup before taking a swig of water and tasting the next. They recorded their opinions on an iPad.

These twins were serving as volunteer subjects for the Monell Chemical Senses Center, a nonprofit research institute in Philadelphia whose sponsors include such food giants as Coca-Cola and General Mills.

“Our question is whether some people are taste-blind and if so, to what? Our interest is whether this is a genetically determined trait,” said Danielle Reed, a Monell behavioral geneticist. “We like to compare genetically identical twins to twins that are no more similar than ordinary siblings.”

This can help food scientists understand which traits — say, an affinity for bitter

flavors — are most strongly determined by genetics. “You can imagine if we look subjectively at their DNA we could predict what will taste better or worse to people,” Reed said. “So you can tailor dietary advice to people’s actual ability to taste and smell.”

Monell was just one of a handful of research groups that attend Twins Days. A few feet away at Procter & Gamble’s Olay tent, scientists were studying twins to better understand the aging process and its effect on skin. Nearby, a forensics expert from the Los Angeles Police Department was collecting latent fingerprints from identical twins to improve fingerprint-identification tools.

At West Virginia University’s tent, biometric researchers took hi-res photos of twins and recorded them speaking to help computer scientists create better facial and voice recognition systems.

“If you can build a system that can differentiate between identical twins,” said Jeremy Dawson, a WVU associate professor of computer science, “then it’s a lot easier to tell the difference between (regular) people.”

Doug and Jill and Phil

and Jenna

Twins Days is also about the science of attraction.

New kings and queens are crowned here each summer. But the closest thing to perennial festival royalty are the Malms.

Gregarious identical twins Doug and Phil Malm grew up in Idaho. Identical twins Jill and Jenna Lassen, both introverts, grew up in Michigan. Their father would address them as “sisters” because he was too proud to admit he couldn’t tell the girls apart.

All four were visiting the Twinsburg festival in 1991 when they met and sparks flew. Luckily, there was never a question over who would be with who.

“It was instant,” said Phil, who chose Jenna. “We knew right away which one we were with.”

The foursome now live in Moscow, Idaho, as members of a tiny subset — identical twins married to identical twins. Doug and Phil, 60, are retired carpenters, while Jill and Jenna, 50, work in day care. All four share one home.

A year’s worth of data

Back at the research tents, the twins lined up, sometimes for an hour or more, to participate. It’s a mutually beneficial arrangement.

The twins enjoyed it because they got money or free samples. Many said they feel good knowing they are contributing to science.

The scientists like it because it’s an efficient way to gather data from a hard-to-find group of people.

The Monell Chemical Senses Center expected to collect research on some 450 twins over the course of the weekend.

“We collect a year’s worth of data in four hours,” Reed said.

(SD-Agencies)