You could say that he is looking for the baby of the family.
Mr Lee Thiam Heng, 76, says his parents, who were Hokkien hawkers on Amoy Street, had 16 children.
The sister he is searching for, Lee Choo Hoon, is the youngest.
He estimates that she should be 60 years old now.
The family was too poor to make ends meet, so they gave her away.
If he could meet her, it would make a great Christmas gift, muses the grizzled gent.
He cannot remember much about her adoption. But her thin and yellowed guardianship papers, found during a round of spring cleaning, states that she was born in Kluang, Malaya.
A week after she was born, she was given away and adopted by a Mr and Mrs Loo Teck Chwee, who were friends of the family.
"She visited our parents when she was in Secondary one. Then her adoptive grandmother began to object, so she stopped," he explains in a mixture of Hokkien and Mandarin.
Two other sisters of his were also given away for adoption.
"We are in close contact with one of them, because her adoptive family never objected to it, but we have lost touch with another sister, who was given away to a Malay family," he says, adding that he does not have the latter's adoption papers.
Mr Lee says the family has been looking for his youngest sister for about two years now.
"We found out that she went to Hua Yi Secondary School, and that her adoptive parents probably changed her name to Loo Su Yun, or Loo Siew Yun. We were hoping to get in contact with her via the alumni. They tried their best to help, but there were no leads they could give us."
He explains that the desire to reunite with their siblings has grown over the years.
"I am getting old, and so are my siblings. Those of us who are still around really hope to gather the whole family together."
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