"Identical twins provide us with a natural experiment or comparison. You have the same genes -- identical people -- yet something can happen to one and not the other. You can look at the health and psychological effects by comparing one to the other."

-- Nancy L. Segal, Ph.D., author, professor of developmental psychology and director of the Twin Studies Center at California State University, Fullerton, Calif.

In 1994, New Mobility announced a physiological study on identical twins -- one with a spinal cord injury -- that researcher Dr. William A. Bauman, director of the Spinal Cord Damage Research Center with the VA Medical Center, Bronx, was to conduct. Soon after, Bauman received a phone call from Kari Krumweide (see page 34), who had an SCI. She and her sister, Kathi, were raised as fraternal twins because of a medical mix-up. She told Bauman they always felt they were identical twins and asked his opinion.

Bauman suspected Kari and Kathi were identicals, and a blood test proved him correct. He paid for their trip to his center for participation in his study. Studying identical twins -- clones -- allows for a perfect control study. "You have the ability to say: What would my body composition, metabolism or exercise tolerance be if I were not spinal-cord injured?" Bauman explains. "We can come up with more precise answers. We were the first research group to clearly show that bone mass decreases with increasing duration of injury."

Along with Kari and Kathi, Bauman studied 15 other sets of identical twins. Though he studied them for physiological changes, he observed that when and how someone became disabled or injured dramatically altered the twin relationship.

"I had one pair where the twin was injured between 1 and 2 years of age," he says. "The nondisabled sister had to grow up with less parental attention and the stigma of having a sister that was spinal-cord injured. She was very angry, so much so that when I dropped them off at the airport, the nondisabled twin wouldn't even pick up her sister's bag. It was eye-opening."

This suggests that twins who become injured at a young age may grow up in antagonistic relationships with their twins. In other cases, nondisabled twins may feel overwhelmingly guilty and shun their disabled twins -- or, conversely -- become willing to do anything for them.

World-renowned Paralympic wheelchair racer and identical twin Scot Hollonbeck, injured at T11 at age 15, agrees with this observation. "Anyone under the age of 25 just doesn't have the ability to process it [the injury]," he explains. "They're not mature enough to accept that life has no guarantees. They don't have the skill sets to understand or manage the feelings that coincide with a traumatic event. With age, we develop better communication skills, better coping skills, better conflict resolution skills."

Brothers in Arms Born in the small, rural town of Balstrop, La., Terry Winkler, now 53, quit school when he was 15 and began working odd jobs. At 18 he was working the offshore oil fields of southern Louisiana. One night after work, while Winkler was handling a friend's .22 Lugar pistol, the gun accidentally went off and the bullet severed his spine.

During Winkler's hospital stay, his identical-twin brother, Kerry, who quit high school a few months before graduating, tried desperately to bring himself to visit his twin. But at 18, he could not bear the pain of seeing his best friend sick in bed. Within a year, the brothers gradually separated and for 30 years saw each other only a few times a year at their parent's house. Even now Kerry's guilt is so strong that he gets choked up when trying to describe his feelings: "I have a lot of regret about that period. Terry was in and out of the hospital a lot at an age when you should be runnin' and goin' and buckin' and snortin' and kickin' your heels and doing anything you can get away with. But I could hardly go by there and see him, I couldn't stand it. I was mad at him being that way and mad about it even happening to him," he adds. "It's really hard to try to put it into words right now ... I feel like I'm going to cry about it."

While Terry recuperated, Kerry says nobody comforted him or explained what was going on and what would happen to his twin: "I do not remember anybody coming to comfort me or talk to me about it. ... Nobody."

Kerry moved to Florida and became a successful mechanical contractor. Terry, while learning to live with his disability, became curious about medicine and fascinated with Reader's Digest anatomy articles. After getting his GED, Terry went on to college, then to Harvard, then to medical school. Now he's a doctor of physical medicine with a practice in Springfield, Mo.

The brothers describe being close to one another as kids -- best friends who played together every day. When they started kindergarten, they spoke a gibberish that nobody could understand, but they understood perfectly. The brothers -- 99.99 percent identical -- have each been married three times; their third wives are both named Janice. Now they love restoring antique pickup trucks: Terry does the bodywork; Kerry fine-tunes the engines.

They agree that the accident caused a break-up in their relationship but neither can explain why it happened. "It was a very painful time," Terry says. "I remember many times crying."

"There were a lot of times I knew something was wrong," Kerry says. "I'd be hurting in my kidneys and I'd call to find out and they'd say Terry's in the hospital again, he's in bad shape."

When Terry was in third grade, an ear infection caused deafness in his right middle ear. About five years ago, Kerry developed a problem and lost hearing in his right middle ear as well.

Terry says that though he felt abandoned by his brother after the accident, he knows there was no forethought or intent on Kerry's part: "But why go there? I'm just grateful we're back together."

"I'd trade it 100 times if I could," Kerry says. "I just hated to see him so bad, but I couldn't be there for him."

I Will Carry You
Unlike twins who experience disability at a young age, when disability occurs at a later stage, those we spoke with say they were drawn closer to their twin. The nondisabled twin wishes they were the one injured or diagnosed; the twin with the disability claims they couldn't have survived without the other. Hollonbeck explains this as the "take the bullet" phenomenon.

"Each thinks the other twin wouldn't be able to handle it," Hollonbeck says. "Both want to take the bullet for the other guy. But it's one thing to say I'll pick the kids up from school. It's another to say I'll take a 50-year disability. Nondisabled twins want to take that burden."

In August 1990, Holly Koester was injured at the T7 level when her SUV flipped over on a temporary road on an Army base in Alabama, where she was stationed. Her mother and sister KC, three years younger, flew down to the hospital. It took some time before Holly's twin, Joy, arrived from Fort Campbell, Ky.

Holly, the leader of the pair, joined the Army in college and convinced her twin to follow. KC joined the Marines, then one of two brothers joined the Navy. "We tried to talk our other brother into joining the Air Force so we'd have all four services covered, but he wouldn't," laughs Holly.

"Growing up, my mom called us 'the twins' until doctors told her not to, then she called us 'the girls,'" Holly says. "When she had KC, we became the girls and KC. After our two brothers were born, we became the girls, the boys and KC."

Joy says the first time she was separated from her twin was in college: They lived on the same campus in the same dorm, but Joy was on one end, Holly on the other. She says many times they'd meet downstairs wearing the same outfit. They were together so much their roommates became best friends. The sisters were athletic and very competitive with each other, but the minute a third person got involved, the twins sided against them.

"I could beat Holly, but nobody else could," Joy says. "She could beat me, but nobody else could."

In the military in Germany, Holly and Joy were stationed across the street from each other. They are so similar in appearance that their soldiers would salute and ask: 'Are you my lieutenant?'

"I had a platoon sergeant who, before he knew that I had a twin stationed nearby, said to me, 'Sometimes you are so friendly and sometimes you act like you don't even know me,'" laughs Joy.

Surrogate Twin Steps In
The twins received marching orders to Desert Shield just prior to Holly's accident, so it took a while for Joy to finally get permission to see her sister in the hospital. When she walked into the intensive care hospital room at the Cleveland VA, she was devastated.

"She is my best friend and has always taken care of me," Joy says. "They would only let us spend a couple minutes with her every couple hours. I'd take a warm wet rag and wash her face off, tell her that everything was going to be OK. But we didn't know what life was going to be after that. It changed everything, our outlook, our priorities."

When Joy was deployed to Iraq for Desert Storm, Holly described lying in bed wishing her sister was with her -- not for herself, but because she knew Joy was in danger. The twins' mom and KC moved into a rented apartment near the hospital. The girls' father stayed home and never visited his daughter in the hospital.

"My father never recovered from the accident emotionally," KC says. "When we found out about it, he immediately said it was his fault because he had convinced Holly to buy a Mustang convertible. We thought Holly flew out of the convertible. When he found out it was her Bronco, he blamed himself for telling her to keep her SUV. He was determined to make it his fault."

The once-healthy man was the backbone of the family, but his health deteriorated. Younger sister KC stepped in and moved the family from their hometown of Buffalo, N.Y., to be with Holly in Cleveland, Ohio.

"My younger sister and I became close while Joy was over in Desert Storm," Holly says. "I think Joy became a little jealous or hurt because she couldn't be as close as before."

Holly expected to make the military a career. Now she "lives" her career by encouraging her sister to move up in rank. When Joy's platoon got called up for Operation Enduring Freedom, she asked Holly to stand in line with her as she loaded her soldiers onto the plane to fly them to Iraq.

"The soldiers go through a line of the whole staff. You shake their hands and wish them well," Holly says. "I was wearing my Army sweat jacket and was in my wheelchair. They knew I was prior military, but my sister let me wish them well with her."

The first time Joy saw her twin in a wheelchair was at the National Veterans Wheelchair Games in 1991. Holly says that first game changed everyone's point of view: "No longer was it 'poor Holly, she's not going to be able to do sports,'" she says.

"It was really hard to watch her struggle and do it, but when she finished, it was such a sense of accomplishment," Joy says. "But watching her go through it was tearing my heart up.

"When she's hurting, I can tell that I need to give her a call because something may not be right," Joy says. "I have no idea why, I just feel it ... she has the same feeling and knows when to call me."

Now Holly volunteers with the Paralyzed Veterans of America as sports director and is on the board for the Buckeye chapter. She receives a pension from the VA and works as a substitute schoolteacher -- "just for fun money, so I can race."

Holly lives 3 miles from KC's accounting office and brings her "surrogate twin" dinner during tax season. Joy lives in Indiana and is in the reserves. Living in different states, the twins only see each other during holidays, special events or when Holly goes through Indiana for a race. They call each other once a week. "Just knowing my sister is still with me is the main thing," Holly says. "I can't think about my life without Joy."

Paralympic athlete Scot Hollonbeck, left, raced -- and beat -- his nondisabled twin, Sean, at the Shepherd Center Peachtree 10K.