Mary Katherine Shull had a childhood full of energy, athleticism and bright promise. She was a state champion gymnast in Tennessee and won best "all-round" in several competitions across the Southeast, all under the guidance of her coach, Ted Hicks, whose apparent commitment to his family and to his faith made him a true mentor in her admiring eyes.
Shull, now 22 years old, said she enjoyed a close relationship with Hicks. "I wanted him to accept me and like me as a person, not only as a gymnast. We really had more of a father-daughter bond."
That was until the night that 40-year-old Hicks climbed into bed with the then-15-year-old Shull, and molested her.
"I was in a hotel room because we were at nationals. I opened my eyes to see Ted there and I'm horrified. I don't know what to do and I don't know where to go. I'm 16 hours from home, alone in a hotel room," she said.
On numerous occasions over the next few years, often during travels to gymnastics tournaments, Hicks would molest Shull. To keep her silent, he manipulated Shull into blaming herself for the abuse.
Shull said, "He told me it was my fault: 'God only gives you what you want' -- and I believed that wholeheartedly. I had so much respect for him."
Young athletes often idolize, even worship, their coaches, but a small minority of coaches exploit those feelings, sexually abusing minors entrusted to their care. It's become every parent's nightmare.
Dr. Robert J. Shoop, who has been chronicling the problem since the 1980s, says the incidents are getting more attention than they once did.
"I think many people feel that adults who abuse children are wearing trenchcoats and hiding in playgrounds. But the reality is the reason these people can molest children is because they're almost above suspicion," Shoop said.
An investigation by Maureen O'Hagan and Christine Willmsen of "The Seattle Times" revealed 159 coaches had been fired or reprimanded for sexual misconduct in Washington state alone over the past decade.
Click here to read the series of investigative reports on coaching and sexual abuse published in "The Seattle Times."
O'Hagan said coaches' desires to keep the abuse covered up coupled with girls' shame and embarrassment has left the problem largely unreported.
But some young women in Washington are willing to speak out. ABC News' 20/20 brought Shull to Seattle to meet young women who shared stories like her own: Abby Rice, Mollie Bryan and Natalie Duryea.
Duryea recalls how her relationship with her basketball coach, Tony Giles, changed from coaching to abuse. She said he began with compliments about her playing and gradually began to compliment her on her looks and personality.
Psychologists call this behavior "grooming."
Duryea said she and Giles had had sex by the time she was 13.
Bryan was 14 when her tae kwon do instructor, Jonathan Novy, stuck his hand down her shirt. Weeks later, Novy had sex with her in a stairwell.
"He said kissing was too personal," Bryan said, "but he was raping me by the time I was 14."
Rice was a soccer standout whose club coach, Dennis Jones, began grooming her at 15 and had unprotected intercourse with her at 16.
"He could have asked me to do anything and I probably would have done it. "As a 15-year-old ... you're infatuated with them," she said.