Police have appealed for information about disabled or retarded children dumped in the New Territories - three of them within a fortnight last month. They include a wheelchair-bound boy and girl found together in Tai Po on December 17. A boy aged about seven with a mental age of three was found in Yuen Long on December 31, while a 10-year-old boy, also retarded, was found in Tin Shui Wai in October. A police source said they might have been dumped by mainland relatives who thought they would be better cared for in Hong Kong. All the children have communication problems and none has any identity documents. It is not known whether the wheelchair-bound pair, found by a security guard in a sitting-out area in Po Nga Court in Tai Wo Road, Tai Po, about 9.30am on December 17 are siblings. The girl is thought to be about 14 and the boy 12, according to police. 'Neither of them can walk and both have communication problems,' a police spokesman said. They are understood to be in hospital undergoing medical tests. The seven-year-old boy was found sitting alone in a playground in Yuen Long Pau Cheung Square at 1.30am on December 31. 'Medical tests have shown that the boy is mentally retarded. He has a mental age of three. He is unable to speak and he needs to be fed by others,' an officer at Yuen Long police station said. The boy was still in Tuen Mun Hospital last night. The other boy, aged about 10, was found in a park in Tin Pak Road, Tin Shui Wai, on October 15. Police said the four would be taken into the care of the Social Welfare Department if their parents or relatives were not identified or did not come forward. 'If they were Hong Kong residents, we could easily find out their identities and track down their parents with the help of the Social Welfare Department or hospitals,' a police source said. While they might be better cared for in Hong Kong, it would be difficult to find adoptive parents for them, the source said. A social worker said the children would be suffering a strong feeling on abandonment, regardless of their intellectual ability. That feeling 'could be strong and lasting when a child lost touch with their parents for no reason,' Kwok Wai-keung, general manager of family and community core business at Hong Kong Christian Service, said. Social workers said it was rare for parents to abandon children, let alone teenagers, in Hong Kong. Philip Yuen Chi-hoi, chief rehabilitation officer at the Hong Kong Council of Social Service, said the reasons were more likely to be related to emotional factors than financial ones. 'It's unlikely that a [Hong Kong] family would be unable to support their disabled children, considering the available sponsored services and government allowance,' Mr Yuen said. 'However, in most of the few cases, disabled children get abandoned at a young age because their families cannot bear the emotional stress. These cases are very perplexing because the abandoned children are already teenagers, and their parents would have cared for them for a long time.' A government source admitted the Social Welfare Department had difficulties finding homes for children with special needs. As at December 31, the department was still seeking adoptive families for 51 disabled or ill children. Figures show that no normal and healthy children were available for adoption through the department.