'Chinese families still tend not to tell their children that they're adopted and keep it a secret for as long as possible,' says Chung Kim-wah, an assistant professor of applied social sciences at the Polytechnic University.

That mindset is partly due to the traditional preference for natural parenthood, but welfare groups and social workers say it's best for adoptive parents to be candid. The youngsters are likely to be distressed and feel a sense of betrayal if they learn the truth about their origins inadvertently.

A local watch maker and his wife, who only want to be known as Mr and Mrs Wong, learned the hard way. For years, they took great pains to keep their son in the dark. But what was meant to be a lifetime secret blew up in their faces when Mrs Wong was mistakenly arrested three years ago while transporting watch samples for her husband. The panic-stricken woman blurted out the truth to her son at the police station. Then 15, their son was so upset by the revelation he ran away from home. The boy eventually returned to the Wongs.

Adoptive parents often feel confused about when and how they should come clean to their children. To help them cope, welfare group Mother's Choice is running workshops to teach parents how to handle the sensitive issue. It also published a bilingual storybook to convey the idea of adoption to young children. The Place You're Meant to Be follows the adventures of an abandoned kitten who finds a home with a family comprising different animals.

Earlier workshops were aimed at expatriates, but the group extended the service to Chinese parents after receiving more inquiries from locals. The next Cantonese session will be held next month, and with an English-language event in September.

'Parents feel frustrated and some seek our advice on what to say to their children when they reach eight or 10,' says Chong Cho, a social worker with Mother's Choice.

It's best to convey the news naturally rather than like a bolt from the blue, Cho says. At the workshop, parents are taught to broach the subject in a light-hearted way through family activities such as story-telling or visits to orphanages. 'The earlier parents disclose the facts to their children, the better.'

Children today are better informed and smart enough to know that their parents may be lying, Chung says.

'The secret can't be kept forever as one day they will need the birth certificate or adoption certificate to apply for legal documents such as identity cards and passports,' he says. 'The trauma would be even more severe if the children discover the truth by themselves.'

The shock can severely hurt the family relationship and youngsters' self-esteem. 'The children would start to wonder what else their adoptive parents are hiding from them,' Cho says. 'Worse, they may think their background is so horrible that their adoptive parents feel it's necessary to cover it up.'

But even the most loving and well-primed parents encounter problems when they find themselves at odds with wilful teenagers.

'We also prepare families to face rebellious remarks from their children one day, like 'You're not my natural parents',' Cho says. 'Such words can be hurtful. But parents should control their tempers and tell them, 'We're your parents. We love you very much and have a duty to bring you back to the right track'.'

Parents should mind their language, particularly when angry. Adopted youngsters may feel insecure, and words said in the heat of the moment can fester for years and undermine the relationship.

Fanny Lam and her husband have done everything possible to prepare their child for the news. The couple began visiting babies in an orphanage with their daughter to help explain the concept of adoption. 'Once, while she was watching a television programme about birth, I told her that it was another mother who gave birth to her. My daughter was three at the time,' Lam recalls. 'I also explained that her natural mother was unable to take care of her, but I would do my best and love her as much as her birth mother.'

Even so, the youngster sometimes fears being abandoned, Lam says. 'So we keep giving her assurance that she's our daughter and we'll love her forever.'

Eva and her husband also planned to adopt before they married, and she quit to look after their baby girl after the application was approved two yeas ago.

Even though her daughter is just three, Eva is introducing the idea of adoption through story books. 'I don't think it will create a barrier between us even when she learns about her background. My daughter will realise how much we love

and care for her as she grows up,' she says.

'Many parents have questions like, How do I tell my child about a cross-culture family and about adoption? How do I tell other people about adoption, and what relationship can be maintained

with the child's birth parents?' Thomas says.

To help address such problems, the group holds monthly meetings at which parents can share experiences and solutions.

For Carsten Schael and his wife, Angela, ethnic background has never been an issue even though they have three adopted children, aged 13, 11 and one, are all Hong Kong Chinese.

'The fact that they're adopted can't be hidden anyway, and we never intend to do so for any reason,' says Schael, a photographer.

'We wanted to adopt instead of having kids biologically because we really like the concept. There are so many children who don't have parents but need a family.

'Adoption is only a way to start a family or to add a family member. Once the procedures are completed, life is as usual. They're all our kids. People no longer think our children are ethnically different from us.

'Because the world is coming together, we need to be more open-minded and more open to different cultures,' he says.

'People say the children are very lucky, but we always say we're very lucky to have them,' says Angela, a teacher. 'My children know that they don't come from my tummy but come from our heart.'