CHATTANOOGA, Tennessee (CNN) -- When meeting Jeff Donohoo, it's not immediately apparent he is a 36-year-old man living with autism. In fact, unless you get him talking about the Atlanta Braves -- one of his true passions in life -- he is a very quiet person.
Early on, his younger brothers and sister didn't know, either.
"Since they grew up with him, they just knew Jeff was Jeff," said Nancy Donohoo, his mother. "They didn't think of him as weird or anything."
But when friends started to notice Donohoo was different, Nancy Donohoo was quick to explain to a group of 10-year-olds why.
"Jeff has a social problem, not a mental problem," she explained. "He's very smart. He reads encyclopedias ... he just doesn't know how to talk to people."
From then on, friends who visited the house always made an effort to interact with Donohoo, through a high-five or a simple "hello."
Today, it's unlikely Donohoo will be the first to say hello in a group setting, but interacting with people is easier for him than it once was.
Questioned about his childhood, his most elaborate response is "yeah" or "no." But when the topic is the Braves, it's hard to get him to stop talking about the latest statistics or his favorite player, Mark Teixeira.
Asked how long he's been a Braves fan, there was little hesitation: "All my life."
He's come a long way since he was a child. Then, just teaching Donohoo to talk was a challenge in itself, Nancy Donohoo said. "There was no eye contact, so I would hold his face in front of me, and say the word I wanted him to say."
Donohoo entered the first grade as a special education student. It was the first year special education was offered in his family's hometown of Florence, Alabama. He carried on with special education until the sixth grade, when he was mainstreamed, or put in classes with children without disabilities.
For most of Donohoo's childhood, his mother had suspicions about his condition. "When he was little, I had watched a 'Marcus Welby' show, and they had an autistic child on there. But he was very passive; he sat in the corner and just hit things," Nancy Donohoo said. "Jeff was wild. He was the opposite, so I just assumed he couldn't be autistic. But he had a lot of those mannerisms."
It was Donohoo's freshman year of high school when Nancy and Bill Donohoo learned what was wrong with their son.
"There was a doctor in Huntsville that dealt a lot with hyperactive children," Nancy Donohoo said. "He said, 'I'm going to give you this sheet of paper; these are all the symptoms of autism.' " The list had 19 symptoms, and Nancy Donohoo was instructed to circle the ones her son had.
The diagnosis didn't change how Nancy Donohoo dealt with her first-born son. In fact, the doctor said she already was doing all the right things, working to socialize Donohoo.
Today, Donohoo, living with his parents, finds comfort in strict routine. He wakes each day at 5 a.m. to make himself breakfast and prepare for work. At 6, Nancy Donohoo drives her son to Memorial Hospital, where he's entering his 16th year of service with the cafeteria.
Ollie Forté is Donohoo's supervisor, and has worked with Donohoo almost since the beginning. "He's very valuable to us at this department. He's dependable, on time, no attendance problems," said Forté. "We love Jeff."
After work, at 2:30 p.m., Donohoo rides with his mother to the YMCA, where he works out for about three hours.
Then it's back home, where he fixes himself dinner and spends hours online looking up Braves statistics, or reading a number of baseball-related books from his personal library.
This cycle repeats on days Donohoo works at the hospital. On his days off, the schedule is equally strict, with little variation. He'll still go to the YMCA, and he'll also make the occasional trip to the bookstore, adding to his collection of baseball-related literature.
Sudden changes to daily plans are still a challenge. "If he's made his plans to do something tonight," said Bill Donohoo, "and we come and say, 'We're going to get something to eat. Do you want to go?' that upsets his plans for what he's going to do that night."
Physical contact is also difficult. "He doesn't like to be touched," Nancy Donohoo said. "He doesn't freak, but he doesn't like it. He stiffens up. He'll want to give you a hug, but he still has a hard time."
The many challenges aside, Donohoo has a fine appreciation for things like cooking. In addition to preparing his own meals, he also enjoys baking.
"He loves desserts -- he loves sweets," Nancy Donohoo said with a laugh. "He's a little heavy, but we're working on that."
Nancy and Bill Donohoo have endured the challenges, and they acknowledge their son will never be fully independent. But one can tell they couldn't be prouder of him.
"It's rewarding today, because he's come so far, but it was a long road," Nancy Donohoo said.