The couple had resorted to searching for sperm donations after discovering that the husband had an inheritable medical condition, according to reports.
The donor allegedly claimed to be Japanese and unmarried, telling the couple he had graduated from well-respected Kyoto University. The woman and the donor had sex 10 times in June 2019 before she conceived, according to Japanese media.
Late in the pregnancy, she discovered that he was Chinese, rather than Japanese, had a wife and was not a Kyoto University graduate.
After the birth, the couple later gave up the baby to a child care facility, the Tokyo Shimbun newspaper reported.
Thriving black market in sperm donation
A total of just 12 hospitals across Japan currently carry out artificial insemination procedures. However, access to such treatment is strictly controlled, even for married heterosexual couples, while single women and gay couples are not eligible to apply.
As a result, a black market in sperm donation is reportedly thriving on social media. The rise of illegal sperm donor transactions has been further fuelled by strict "right to know" laws in Japan, which means children are legally entitled to identify their donor parent.
This has led to a growing number of donors seeking unofficial methods of donation in order to preserve their anonymity, via social media platforms and websites.
An estimated 10,000 children have been born in Japan from sperm obtained through this type of third party, according to media reports.
In a further reflection of the challenges facing prospective parents, Japan has just one official sperm bank, the Mirai Life Research Institute, which opened last year in a bid to help ease shortages and safely find donors.
At the time, its director Hiroshi Okada, warned media that as many as 96 per cent of more than 140 websites advertising sperm donor services were unsafe.
