A man who was conceived through artificial insemination using sperm from a donor sent a letter to a university hospital last Friday asking it to disclose information about his father.
A written request for such information is extremely rare, and it is likely to trigger nationwide debate on the right of the man to know his birth parent.
Hideaki Kato, a 40-year-old doctor who lives in Yokohama, said he wants Keio University Hospital in Tokyo, which conducted the fertility treatment, to tell him who his father is.
The university has said it is unable to do so because the records containing that information have already been destroyed, and because the treatment was performed on condition that the donor would remain anonymous. As such, the hospital would not be allowed to divulge the information even if it was still available.
"Since it has been about 40 years (since the treatment), records (including those pertaining to Mr. Kato) have been destroyed so we can't confirm who the donor was," said Yasunori Yoshimura, a professor of obstetrics and gynecology and head of the university hospital's artificial insemination program.
Kato said he was a medical student in December 2002 when he learned while training for blood tests that he and his father were not blood-related.
"I still have this feeling that half of my body was created by someone whose name I do not even know," Kato said.
Yoshimura said all records from 1995 have been archived.
However, he said that under current regulations, information about sperm donors can't be disclosed in principle because donors have agreed to take part in the treatment on condition of anonymity.
Over the years, more than 15,000 babies have been born in Japan via artificial insemination involving a donor.