''She was a typical Chinese mother. Despite the fact that her son has been in a bad mood for some time, she did not expect this sudden outburst of rage.'' The teacher said that after the incident, the mother had withdrawn from her son for fear of another violent scene and both parties had resorted to silence.

In another case last month, a teenage boy was charged with manslaughter for beating his mother to death. The High Court heard that the 16-year-old lashed out in a fit of rage after his mother scolded him for not eating more vegetables.

Teachers and social workers believe these are not isolated cases.

Pauline Chow, a secondary school teacher and member of the working group in support of schools with Band Five (low academic achievers) students, said parents who were uneducated were most at risk.

Children in such families felt superior to their parents because of their additional schooling and usually gained the upper-hand in confrontations, she said.

Often such parents had not received compulsory education when they were young and many were illiterate. ''Some children treat their parents like simpletons,'' she said.

''Some of these parents cannot even read school report cards because many are written in English. So children can keep parents in the dark over their academic progress.

Child bullies come in many forms. The most common method is to verbally ''blackmail'' parents with threats of running away - which taps a deep-seated fear in many traditional families.

Other children throw sudden tantrums. They become bossy and rude to get what they want. These tantrums often involve breaking objects and sometimes throwing them at parents.

Hitting siblings is another way to hurt parents. And in its extreme form, children resort to physical violence against their parents.

A major reason for the loss of respect for older people is that many young people don't want to be controlled now, Ms Chow said.

''These days children have this mentality that if they are not upsetting other people's lives, they should be left alone to go about their own business.

''They think they are always right and can always justify their actions even if it means doing things their parents don't approve of,'' she said.

''To challenge them is like asking for trouble.'' Youth-line counsellor, Ms Hon (whose full name cannot be disclosed for professional reasons), agreed and said the clash between old values and the changing society caused conflict.

''It is common these days for both parents and children to use abusive language to hurt each other. But it is not always the children who are at fault, the parents too are responsible,'' she said.

''Under peer pressure and other social influences such as the media, children as young as 11 and 12 want to have more freedom and independence, and parents often don't realise this.

''As the result, there is a breakdown in their relationship because both parties fail to understand each other. Once a voice is raised, arguments ensue.'' Ms Hon pointed out that the mother was often placed in the difficult role of family mediator. Her husband expected her to discipline the children while the children asked her for more freedom.

''If the children get out of control, the father blames the mother for failing in her duty,'' she said.

A major source of increased tension across the social spectrum is the lower age that young people start to date.

According to Ms Chow, boy-girl relationship issues such as lengthy phone calls and going out without permission top the list of factors which cause tension between parents and children. Others include not doing homework, gambling on the horses, spending too much time at video games centres and watching pornographic videos.

Ms Hon said it is hard to determine which of the above factors contribute most to parent-child tension but agreed that young people had started dating at an earlier age in the last few years.

''A lot of children want to keep this from their parents and it is true that problems stemming from this have increased tension in families,'' she said.

Ms Chow feels the trend had started in the mid-80s with the rise of local popular culture.

Fortunately, in Ah Wai's case, the family came to terms with the problem. Through the teacher's mediation Mrs Lee became aware that her son had been unhappy at school - a new one with hard-working students and tougher syllabus. His phone calls to an old classmate, a girl, were his way of escaping his predicament.

Ms Chow says that mediating through a third party can often help parents and children to understand each other better.

Parents can ease the situation by being less severe when it comes to supervising their children. ''But children also have to learn to be more self-disciplined. Leaving them alone to cool down can be a temporary measure [to settle an argument] but at the end of the day, both sides have to compromise.''