More than 500 women in Japan made use of a major Denmark-based sperm bank in the roughly three and half years through last October, a recent report by the company showed, highlighting growing domestic demand for the service.

Cryos International, the world's largest sperm bank with around 1,000 registered donors, has sold sperm to single women, sexual minorities and women with infertile husbands in Japan since officially launching local consultation services in March 2019.

Supplied photo shows Hiromi Ito, the head of Cryos International's Japan operations, at an academic conference on fertility treatments in Kobe, western Japan, in November 2019. (Kyodo)

With only around 150 clients in Japan tallied in November 2020, recipients have jumped more than three-fold in the roughly two years to October 2022.

A nonpartisan parliamentary group is deliberating on legislation for assisted reproductive technology using donated sperm or ova in Japan, but an outline of a bill last March showed that commercial transactions would be prohibited.

Hiromi Ito, who heads Cryos International's Japan operations, has expressed her willingness to begin recruiting donors in Japan, saying that "women who want children will not give up and will turn to person-to-person transactions, which involve risks such as infectious diseases."

"I would like (the government) to create an environment where private sperm banks can operate under certain rules and safety controls," Ito added.

Donors at Cryos International, the majority of whom come from the United States and Europe, can either be anonymous or consent to an ID release, where identifying information is disclosed when the child comes of age.

The report showed that 70 percent of clients in Japan chose non-anonymous donors, suggesting many believe that a child has the right to know their origins.

User surveys conducted in 2021 and 2022 showed that 35 percent of the 246 respondents were married, while 13 percent were in same-sex relationships and 52 percent were single.

The report estimates that sexual minorities make up between 30 to 40 percent of all clients. Consultation data indicates that unpartnered lesbians and asexuals make up a share of those who are single.

"The desire to have children is a lifestyle choice, and it is unacceptable to discriminate based on gender identity or sexual orientation," said Shuhei Ninomiya, a professor emeritus in family law at Ritsumeikan University.

While the Japan Society of Obstetrics and Gynecology stated in its proposal in 2021 that assisted reproductive technology using donated sperm or eggs would be limited to infertile heterosexual couples, it has noted the need to respond in the future to increasing demand from sexual minority couples.

Satoko Nagamura, the chairperson of Kodomap, an organization advocating for sexual minorities who wish to have children, stressed that the government "should not exclude sexual minorities from assisted reproductive technologies when enacting legislation."

Yoshie Yanagihara, professor of bioethics at Tokyo Denki University, said the issue is not only for women.

"Commercial sperm banks put a price tag on men supplying sperm and sell their genetic information," Yanagihara said. "I would like men, as well as women, to consider this issue...about whether we should live in a society where people's genetic information is evaluated and traded for money."