But sports as an environment for sexual abuse is hardly new. Experts say it has all the significant ingredients that can lead to such abuse: coaches have close relationships with children and unsupervised access to them, while holding a position of trust and authority that can often keep children from reporting the problems to their parents or other authority figures.
"It's not new, but in sports it seems we are doomed to be shocked and appalled all over again," said Dr. Sandra Kirby, an associate vice president for research at the University of Winnipeg, who led a study in the 1990s that found widespread instances of sexual misconduct involving coaches of the Canadian national team in various sports.
There have been no large-scale studies of the number of children abused by coaches, said David Finkelhor, lead researcher for the Crimes Against Children Research Center at the University of New Hampshire.
"It would be helpful to have an idea of what the numbers are," Finkelhor said. "Because it is a large-risk environment. I don't believe it's that abusers are attracted to this more or less than any other profession, but it affords more opportunity. There is a lot of time spent traveling together for games, training after school away from the usual school environment. They are undressing in the locker room and showering."
According to Thomas Plante, a psychology professor at Santa Clara University who has studied and treated pedophiles, including many priests, about 5 percent of all men have a predilection to be sexually attracted to children. Some set out to act on those impulses, but others, he said, "sort of fall into it."
"They have unsuccessful adult relationships or other problems in their lives and they get involved with kids as a coach and one thing leads to another and that leads them to sexual behavior," Plante said.
That is precisely what happened with one of the patients of Dr. Fred Berlin, the director of the Sexual Behaviors Consultation Unit at Johns Hopkins Hospital. On the referral of Berlin, the man spoke in a telephone interview about his experience as a youth baseball coach who sexually abused a boy.
He pleaded guilty to the charge and served prison time in 1983. He has undergone years of therapy to help keep him from acting on his attraction to boys, he said. He did not want to identify himself for the article because of the lasting stigma attached to his offense. He is 66 now and living in the Baltimore area, where he is registered as a sex offender.
"I loved sports, I loved baseball and I felt I was pretty good at coaching, so it just evolved," he said. "It just happened to put me around young boys and, unfortunately, that's not where I need to be.
"There were times I tried to gain control over myself, but it kind of took control of my life. By the time I got arrested, I knew I needed help."
The man said he pleaded guilty because he did not want to subject the boy to any more trauma, and found Berlin's program before he was sentenced. Therapy, he said, has given him a set of tools to deal with his attractions and not act on them. He also said that he created boundaries for himself so that he is never alone with a child.
The man said he had no independent knowledge of the case of Sandusky - the former Penn State assistant football coach who has been charged with assaulting 10 boys - but said he had watched and listened to Sandusky's public statements and explanations of his behavior.
He said interviews suggested that Sandusky did not understand the harm abuse can do to children. "I did try to send information about Dr. Berlin's program to his attorney, but you have to recognize you have a problem before you can get help," the man said.
The vast majority of sexual abuse cases are perpetrated by male coaches. Many of the scandals that have emerged over the years have involved those male coaches abusing girls, including one that led to the recent decision by USA Gymnastics to bar Don Peters, the coach of its 1984 women's Olympic team, from coaching for life after two of his former athletes came forward accusing him of sexual abuse.
The number of cases of male coaches abusing boys over the years is unknown, although most experts speculate that there have been many, and that they have simply been slower to surface.
One of the first high-profile cases came in 1997, when the former N.H.L. player Sheldon Kennedy accused his junior hockey coach, Graham James, of abuse. James served three and a half years in prison after being convicted on 350 charges in 1997 and pleaded guilty in Winnipeg, Manitoba, last Wednesday to a set of new charges, including those brought by another former N.H.L. player, Theo Fleury.
The latest case has arisen in Memphis, where the police confirmed they are investigating abuse charges by two men against Bobby Dodd, the longtime chief executive of the Amateur Athletic Union.
The abuse of boys has more barriers to being reported than the abuse of girls, partly because of the hypermasculine culture of sports.
"Abuse of girls is underreported, but abuse of boys is even more so," Plante said. "It taps into homosexuality fears and just freaks them out. Kids think it's something about them, that they somehow asked for it. Boys feel they are less likely to be believed than girls."
Girls are still far more likely to be abused over all. In the most recent study by the Crimes Against Children Research Center in 2009, involving 1,175 children ages 14 to 17, 9 percent of girls reported unwanted sexual contact by an adult in their childhood; 1 percent of boys did.
Chris Gavagan, a filmmaker who is making a documentary on sexual abuse in sports called "Coached Into Silence," based largely on abuse he said he endured from a youth hockey coach starting when he was 14, is among those who believe the problems for boys in sports are much larger than suspected. Not only does it happen more than people want to think, he said, but the culture of sports works against a child trying to report it.
"Sexually abused boys are going to be the most silent group," Gavagan said, adding that the allegations involving Sandusky, if true, fit a familiar pattern.
"With the whole macho atmosphere of sports, it seems to be the perfect storm of circumstances," he said. "There's the culture of personality that keep these guys the kings of their little kingdoms, the sense of hero worship. The kinds of things Sandusky was offering those boys is every boy's dream - trips to bowl games, going down on the field. It allows these things to go on for a long time. And when you don't tell someone the first time it happens, you already feel complicit."
Gavagan has become involved in the rush to respond to the allegations against Sandusky and Fine, including testifying in front of a Pennsylvania legislative committee supporting laws requiring people to formally report to the authorities any allegations of sex abuse.
Other solutions discussed include establishing the kinds of enforceable boundaries that other organizations with potential for abuse have adopted.
Plante said that groups like the Boy Scouts and Boys and Girls Clubs have instituted rules forbidding any adult leaders to be alone with children who are not their own.
And with leaders, parents and children aware of the policies, everyone is a bit more vigilant about the boundaries that pedophiles generally start to push before they abuse a child, the experts said.
Much of that came about after the first revelations of how the Catholic church dealt with pedophile priests.
"One of the things the Catholic church scandal did was show nonprofit organizations there was a huge financial liability there," Finkelhor said. "So, many of them got to work trying to prevent one of their own."
Sports, though, have lagged far behind, with few sports organizations or schools employing much in the way of prevention strategies. Many youth sports groups have turned to requiring background checks on coaches - the National Council of Youth Sports has urged all leagues to use them - but that only flags pedophiles who have already been caught.
So while child sexual abuse is decreasing over all because of increased awareness, Finkelhor said, sports might not yet have joined that trend. So its scandals still have the power to shock.