Updated

More than 4.5 million children are forced to endure sexual misconduct by school employees, from inappropriate comments to physical abuse, according to an exhaustive review of research that reads like a parent's worst nightmare.

The best estimate is that almost one in 10 children, sometime between kindergarten and 12th grade, are targets of behavior ranging from unprofessional to criminal, says the report for Congress by Charol Shakeshaft, a professor at Hofstra University's School of Education (search).

"Most people just don't think this can really happen," said Shakeshaft, hired by the Education Department (search) to study the prevalence of sexual abuse in schools. "We imagine that all teachers are like most teachers, in that they've gone into teaching to help children. Most do, but not all. We need to acknowledge that's the case and do something to stop it."

The report, required under the No Child Left Behind (search) law and delivered to Congress on Wednesday, is the first to analyze the field of research about sexual misconduct at school.

Some educators immediately took issue with its approach, mainly the combining of sexual abuse with other behavior, such as gestures or notes, into one broad misconduct category.

But another prominent researcher supported the findings, suggesting, as Shakeshaft did, that they may even understate the problem. And the American Association of University Women, whose surveys of students were at the core of the new report, stood by its research.

There have been no nationally financed studies to collect data about how common sexual misconduct is in school, one of many areas Shakeshaft suggests must be addressed. Her analysis covered almost 900 documents and reviews that have dealt with the topic in some way, from private research and newspaper stories to reports for government agencies.

What she found portrays a problem that, no matter how uncommon, united groups of teachers, superintendents, parents and education leaders in concern — and disgust.

The report describes schools as places where abusers come to prey, targeting vulnerable and marginal students who are afraid to complain or unlikely to be believed if they did. It describes adults who trap, lie and isolate children, making them subject to unwanted behavior in hallways, offices, buses or even right in front of other students in class. And the offenders work hard to keep kids from telling, threatening to fail or humiliate them.

Misconduct is defined in the report as physical, verbal or visual behavior, from sexually related jokes or pictures of sex to fondling of breasts and forced sex. Shakeshaft did not limit her review to sexual abuse because, she says, that would exclude other unacceptable adult behaviors that can drive kids from school and harm them for years.

Yet spokesman Michael Pons of the National Education Association (search), a union of 2.7 million education workers, said: "Lumping harassment together with serious sexual misconduct does more harm than good by creating unjustified alarm and undermining confidence in public schools. Statistically, public schools remain one of the safest places for children to be."

The NEA, he added, takes any sexually inappropriate behavior seriously, training teachers and working with the Education Department on rules banning harassment in schools.

The other large teachers union, the American Federation of Teachers (search), also found fault with the report's description of misconduct, and Eugene Hickok, the deputy education secretary, said the findings were so broad they may be viewed as "insufficiently focused." But those officials, too, did nothing to downplay the importance of the problem.

"Clearly, sexual predators have no place in public schools," said John Mitchell, deputy director of educational issues at the AFT. "We support background checks, and when someone has gotten through, they need to be removed. And other inappropriate behaviors must be attended to, also, we just really need to have an effort to separate the two."

The report found teachers are the most common offenders, followed by coaches, substitute teachers, bus drivers and teacher aides. Among students, 56 percent of those targeted are girls, and 44 percent are boys, a smaller gap than commonly expected, Shakeshaft said.

Robert Shoop, a Kansas State University professor of education law and expert on sexual exploitation in schools, said the estimate of one in 10 children affected is not high. The actual number may be larger, he said, because of historical underreporting of the problem.

"Children need to be very clearly educated about inappropriate behaviors, and teachers do too, so when children see the earliest signs of this behavior, they have someone to tell," Shoop said. "But often, parents say, 'Mind your teacher.' So it's very unlikely that this 10-year-old kid is going to rip the teacher's hands off and say, 'Back off.' "