Conrad would return from his Primary One classes each day with six to eight sets of assignments, she says. He did them very slowly, so they weren't always completed when he turned in at midnight. Anxious for him to do well, Tang kept a close eye on his homework and made sure he put in two more hours of study before he left for school every morning.

This made her son feel anxious and tense, which soon became an obstacle to his learning.

'Once, when I dictated a Chinese word to him, he forgot how to write the character each time, although we repeated it 10 times,' she recalls. Still, she was gratified when Conrad came home with results from his first exam: he got 80 marks in Chinese, 90 marks in mathematics and earned an average score of 88.6.

'The whole family celebrated in a dinner,' she says.

But her jubilation evaporated when his report card arrived the following week, ranking him 33rd in his class of 37 pupils.

'The best students scored 99.9 marks,' she says. 'Over half of the class had 100 marks in mathematics. My son's 90 marks in mathematics was the lowest in the class.'

Tang was distraught and set an even more demanding schedule for the boy. He would have tuition three days a week, and there was no television and no playtime.

'I couldn't face the fact that my son wasn't better than others,' she says. 'I made him do lots of extra exercises in Chinese, English and mathematics. He couldn't rest and worked until two in the morning.'

Not surprisingly, Conrad flagged, and his frustrated mother started shouting abuse at him. Then the caning began.

'Caning was like a trap,' Tang recalls. 'It dragged me deeper and deeper.

'I first hit him on his limbs. Then I slapped his face and threw furniture at him. Whenever I caned him, he would run. I chased after him and even asked my helper to block his way.'

Tang gave little credence at the time to the principles of child psychology she had learned at university in Canada. Conrad's school results went from bad to worse under her tough regimen. 'He got zero for dictation. His brain went blank because he was so scared that I would beat him if he failed.'

Despite feeling heartbroken, she continued with the beatings, and the boy began to rebel. But a chance discovery when he was in Primary Three awakened Tang to how the relentless drive for good grades was crushing her son's interest in learning - and their relationship.

She surprised the boy scribbling in his room one day, prompting him to immediately crumple the piece of paper and throw it into a bin. The curious Tang later retrieved it and was shocked to find a very unflattering sketch.

'He drew me as a very ugly, witch-like woman,' she recalls.

'It was horrific. I told myself: 'This is your report card as a mother.' It is very painful to find that your child hates you.'

Then pregnant with her younger son, Tang was devastated and sat sobbing for hours.

But when the tears dried up, she started anew. First, she transferred Conrad to an international school where children could learn at a natural pace. Then she quit her job at RTHK to be a full-time mother.

'I wanted to rebuild our relationship,' she says.

Looking back, Tang traces her unrealistic expectations of Conrad back to her own childhood, when she lacked attention and self-esteem. Pushing her son to succeed was a way to compensate. 'I came from a poor family, and my parents quarrelled and fought endlessly. I felt very unhappy, insecure and helpless as a child. Suicidal thoughts haunted me all way through.'

She was still feeling very low when a community group invited her to give a talk about her parenting experiences. 'I thought I was the worst mother and walked around with my head down,' she says.

Instead of painting a rose-tinted picture, Tang gave a frank account of the painful lessons she learned, bringing many mothers to tears.

'At first I thought they were sad for me. But later, I learned that my speech reminded them of the way they treated their own children. They were crying for themselves.'

The encounter helped Tang realise that her problems weren't unique. It inspired her to make changes in her own life, and also to help other parents.

Tang dug up the psychology texts that she had packed away and eventually came up with a parenting approach that ruled out any beating, abuse, blame, threats or dark looks.

After a year as a reformed parent, Tang began to notice changes in Conrad, too. He enjoyed reading, going to school, and he smiled a lot. He even did well in his studies. 'He was motivated to do his homework and I only coached him when he had difficulties,' she says.

Parents often want their children to be the best at everything. But Tang says each child has a unique set of talents. The parents' job is to help their children discover their potential and encourage them to develop it. By dropping expectations that their sons be the best but encouraging them to do their best, Tang reckons she and her husband have raised confident individuals.

Her younger son, Eugene, is a self-motivated 14-year-old who enjoys playing violin. Conrad, now 22, graduated from the University of Hong Kong with first-class honours in English literature, and now works as an editor in an English-language publishing house.

'When you treat your children with love and respect, they will love you in return and want to do things that can please you,' she says.