(CNN) -- What do Bruce Willis, Winston Churchill, Marilyn Monroe and King George VI have in common besides being public figures? They all suffered from stuttering at some point in their lives.
But what is stuttering and how it does it manifest itself? The Stuttering Foundation of America explains on its website that it is "a communication disorder in which the flow of speech is broken by repetitions, prolongations, or abnormal stoppages of sounds and syllables."
In February 2010, a group of researchers published a study in the New England Journal of Medicine, which states that the brain cells of people who stutter have three genetic mutations; this causes problems in the cells' metabolism.
"This process is called the garbage can, or more like the recycling bin, of the cell. When this process gets interrupted, the cell goes haywire, and that causes problems," the study's co-author Dennis Drayna told CNN.
According to the National Institute on Deafness and Other Communication Disorders, 1% of the world's population, around 68 million people, stutter.
One of them is Sophie Gustafson, a Swedish golfer who has been professional for 18 years, winning 28 titles on the most prestigious tours and earning over $6.3 million, proving that stuttering is not an impediment to succeed.
During September's Solheim Cup, a biennial international match played between a U.S. and a European team, Gustafson wrote on her official blog: "I decided to leave my comfort zone and give my first TV interview."
Gustafson decided to speak to the Golf Channel. The editing team worked for two hours on the 70 minutes it took her to answer nine questions. The result? A three-and-a-half-minute interview.
The 37-year-old told CNNMéxico: "With help from people with good hearts and a little patience maybe a stutterers story can get out there.
"I've always had it, ever since I first started speaking. Both my older brothers had it too, but by the time they started school it disappeared. Unfortunately I wasn't that lucky."
Nonetheless, she had unconditional support from four boys who attended the same school as her, a quartet Gustafson describes as "the cool kids." She also explained how sports were key to her development.
"I was very good at all sports growing up and I think that played a huge part. I always played with the boys and I was always the first one to get picked for any team."
In first grade she began speech therapy in the school's facilities, but far from helping it increased her feelings of isolation.
"it just made me feel singled out and enlighten my problem, that I didn't really see as being much of a problem," Gustafson said. "We really didn't do much; we played different games, probably some that made me say or repeat different words."
Eventually Gustafson left therapy, spending her high school years focusing on her game. She was not the best amateur and could only make it into the 'B' team, but the real challenge came when she had to make new friends.
"Because of my stutter I tend to go where it's safe and people know me, I don't venture out and try to meet new people unless it's forced upon me.," she said.
Gustafson decided to give speech therapy another shot, commiting to twice-weekly sessions with her therapist for six months.
"She was really good and I think it helped me," she reflected. "But it's too hard for me to translate what I learned into real life."
Gustafson couldn't leave stuttering behind, but she clung to golf, and in 1994 the Swede got her Ladies European Tour (LET) membership. This new professional opportunity forced her to once again meet new people, so she sought help from her family.
"I had my brother out with me the first summer so he kind of got me going," she recalled. "He is a very social and all around great guy so I just tagged along with him... I had my dad helping me with flights, booking them over the phone."
By 1998, Gustafson had won three times on the LET and received the Player of the Year award once. It was time to join the world's largest and most dominant women's Tour, the Ladies Professional Golf Association (LPGA).
Three LPGA titles and four years later, she decided to try another treatment at the Hollins Communications Research Institute in Virginia, founded in 1972 to investigate stuttering with scientific methods and new treatment approaches.
"That was a three-week intensive course which was very good, but again, back in real life, I had a very difficult time using what I learned."
None of the treatments she tried in different stages of her life worked. So when she won the Chick-fil-A Charity Championship, she asked someone else do gave the winner's speech for her.
"I would've loved to have made the thank you speech instead of having Nancy Lopez do it for me, but because of my stuttering it would've been Monday by the time I finished," she wrote in a Sports Illustrated article.
Gustafson's impediment is severe, but she still feels fortunate to have achieved all she has within golf.
"The best thing is to have been lucky enough to go where I've gone," Gustafson said. "It's important not to care what people think and just do what you want to do. If they have a problem with that, that is exactly that, their problem."