ROME -- A man throws his four-year-old niece off a roof because she was disturbing his television viewing. Teachers run a child pornography ring. A teen-ager accuses her mother of auctioning her virginity to the winner of a pastry-eating contest.

These three incidents, occurring within days, shocked Italians, who have come to believe that affection for children was part of their national psyche.

These were the most squalid in a series of child abuse cases, but they sounded an alarm that sent government ministers and sociologists scurrying to fathom what the wave of violence against minors meant and what to do about it.

"I think there is a generalized increase in violence and unfortunately the weakest, the children, are those who pay," said Sergio Piro, a Naples psychiatrist.

Others suggested that violence behind closed doors in Italian homes has been going on for some time. The recent highly publicized episodes have merely brought a long-standing problem into the open.

"These cases have made everybody think a little bit," said Ernesto Caffo, a child psychiatrist and government consultant who is considered Italy's leading expert on child abuse. "Certainly the collective conscience in Italy finds great resistance in confronting this problem," he said.

"Making people understand that it could happen in the house next door or in your own home is very difficult because Italians still think it happens mostly in other countries or only to people on the fringes of Italian society," he said.

Caffo, secretary general of the Italian Association for the Prevention of the Abuse of Children, said there are an estimated 20,000 mistreated children in the country.

About 25 percent are sexually abused, 25 percent more suffer serious physical violence and the rest are neglected.

In the most shocking recent incident, Mario Miraglia, 26, a bricklayer in southern Caserta, threw his 4-year-old niece Anna off a roof to her death on Nov. 4. The reason: Anna kept changing television channels with a remote control switch while he was watching soccer.

In central Bologna, one of Italy's most prosperous and socially progressive cities, six men, including two teachers, a photographer and a children's sports coach, were arrested this month for molesting preteen boys and circulating their nude pictures within a child pornography ring.

In Palermo, a trial that ended on Nov. 7 brought the type of sordid details usually found in scandal newspapers into Italians' homes on evening news programs.

Jolanda Greco, now 16, accused her mother of trying to initiate her into prostitution when she was 14 by "auctioning" her to two men.

The deal, according to Greco's testimony at the trial, was that the man who ate more cannoli -- a Sicilian pastry -- won a night with the girl.

Santo Cardovino, 20, the "winner" of the bet and father of Greco's six-month-old baby, was accused of rape. The court acquitted him and Greco's mother on grounds of insufficient evidence -- a controversial Italian legal formula meaning the court believed they could have been guilty but it needed more proof.

Greco's lawyers have appealed the verdict, which was condemned by feminist groups and publicly questioned by politicians and sociologists.

"The city does not applaud this verdict and is in solidarity with the girl," Palermo Mayor Leoluca Orlando said.

Rosa Jervolino, a government minister, called the Palermo acquittals "frightening."

"We don't want there to be two types of violence against children, . . . those committed by society and those committed by the state when it is not able to render justice," she said.

There is less child abuse in Italy than in most other European countries, Caffo said, but Italians were slow to recognize the problems that do exist "because of this stereotyped image, in Italy as well as abroad, that all children are treated well here."

Last June, Caffo launched "Blue Telephone SOS Children," a privately funded 24-hour hotline that children in danger, or adults, can call to seek advice or help. It has received about 8,000 calls so far.

Blue Telephone's team of psychologists will either alert local authorities of imminent danger to a child or find a social worker to help.

Recently a girl who had seen the S0S number in a children's magazine called from a northern city and said, "I noticed in gym class that my friend has bruises all over her body."

A local social worker was alerted and is now assisting the family of the battered child, whose father had taken to drink because he lost his job.

Caffo said Blue Telephone was started "almost as a provocation to make the country reflect on a reality that exists and the lack of public structures to confront it."

Next year he and three other experts appointed by Jervolino are to present new legislation and propose a government office to protect children.