Japan's Ministry of Justice issued administrative guidelines in 2011 covering everything from hair length to hormone therapy for transgender inmates. Fifteen years on, the framework is still under legal challenge. Taiwan, meanwhile, offers correctional officers a single sentence to work with: "strictly segregated by sex."
Japanese society has grown considerably more accepting of gender diversity in recent years. But one institution has resisted easy answers. That institution is prison.
If a transgender woman — someone assigned male at birth, legally still male, but who identifies as female — is convicted of a crime, which facility should receive her: a men's prison or a women's? The question sounds simple. In Japan, it has generated more than two decades of litigation, petitions, and unresolved debate.
Japan's Current Rule: Whatever the Family Register Says
Japan's Ministry of Justice currently takes a blunt approach: it follows the family register (戶籍). Male on the register means a men's facility; female means a women's facility.
Even when an individual has completed gender reassignment surgery and presents entirely as female, she will in principle be housed in a men's prison if her family register has not yet been amended. Facilities manage the resulting risks through solitary confinement and staggered bathing schedules.
The framework is under growing strain. Reform advocates argue that transgender inmates face significantly higher risks of sexual violence, bullying, and discrimination than the general prison population. Some experience severe psychological distress when hormone therapy — already underway before incarceration — is interrupted during their sentence.
Opponents raise a different concern: if a person who retains male biological characteristics is placed in a women's facility, how are the safety and privacy of female inmates protected?
Real Cases That Forced the Question
The debate has been shaped by a series of concrete cases on both sides of the Pacific.
In 1991, in the state of Maine, a transgender woman who had not yet completed surgery was housed with female inmates at her own request. A cellmate sued, alleging a violation of privacy.
In 2001 in Japan, a transgender woman who had undergone gender reassignment surgery abroad was detained on drug charges and processed as male throughout her detention. The case drew extensive media coverage and marked the first time Japanese society seriously engaged with how transgender detainees should be treated.
In 2006, also in Japan, a transgender woman whose family register still listed her as male brought a legal action after prison staff forcibly gave her a crew cut — standard practice for male inmates. The Japan Federation of Bar Associations (日本弁護士連合会) subsequently submitted a formal petition to the Ministry of Justice on her behalf.
More recent cases have complicated the picture in the other direction. In 2023 in Scotland, a male-bodied inmate who identified as a transgender woman was transferred to a women's prison, triggering strong protests from female inmates before being returned to a men's facility. That same year, a Danish court ruled that a transgender woman who had legally changed her registered sex but had not undergone surgery should serve her sentence in a men's prison.
Countries have moved toward different solutions. Some use surgical status as the deciding criterion; others have established dedicated transgender housing units. Italy opened what is considered the world's first transgender-exclusive prison facility in 2010; Los Angeles followed in 2012 with the United States' first unit designed specifically for transgender women.
Japan's Guidelines: Built Through Litigation, Not Legislation
Japan has never formally written transgender detention policy into statute. The system operates through administrative guidelines issued by the Ministry of Justice — guidelines built incrementally over years of lawsuits, petitions, and public controversy.
In 2011, the Ministry issued the Guidelines on the Treatment of Inmates with Gender Identity Disorder (性別認同障礙等之被收容人處遇指針), revised again in 2015. The document classifies transgender inmates into four categories: those diagnosed with gender identity disorder by two or more specialist physicians; MTF (male-to-female) inmates; FTM (female-to-male) inmates; and others who have submitted relevant documentation or been examined by a designated physician.
The level of operational detail is considerable.
Bathing and physical examinations.
Transgender women who have substantially altered their appearance — particularly those who have had relevant surgery — should where possible be supervised by female staff. Those whose appearance has not changed should be attended by multiple male officers. Bathing and strip searches must be conducted individually, with screens available to protect dignity.
Hair.
Male inmates in Japanese prisons are ordinarily required to shave their heads or keep their hair very short. Transgender women who object may be granted an exemption on the grounds that enforcing the rule would be counterproductive to rehabilitation. They may bring their own hair conditioner and styling products; those who wear their hair long may bring their own hair clips.
Clothing.
Dress is determined in principle by the sex on the family register. Transgender women who have undergone breast augmentation surgery may, however, wear a brassiere. Transgender men are not permitted to wear chest binders — a provision legal scholars have criticised as internally inconsistent.
The Hardest Problem: Interrupted Hormone Therapy
The most contested issue in the guidelines is hormone therapy.
For transgender individuals whose hormone-producing organs have been surgically removed, interrupting hormone replacement therapy produces immediate symptoms comparable to menopause. For those who have not had surgery, stopping treatment can cause menstruation to resume or facial hair to regrow, leading to emotional instability and depression. Some Japanese legal scholars have argued that for inmates who have already completed surgery, the suffering caused by forced interruption of hormone therapy approaches the threshold of "cruel punishment" prohibited by the Japanese Constitution.
The Ministry of Justice guidelines take a different view, stating that failing to continue hormone therapy "does not immediately cause harm to daily life that would be irreversible." This provision has been widely criticised for failing to respect inmates' dignity and personal autonomy, and continues to generate legal challenges.
Taiwan: A Near-Blank Page
When Taiwan amended its Prison Act (監獄行刑法) in 2020, it replaced the original language — "women shall be imprisoned in women's prisons" — with the more neutral formulation "strictly segregated by sex." It went no further. How transgender inmates should actually be housed remains legally unaddressed.
The Legislative Yuan has passed a supplementary resolution calling on the Ministry of Justice to provide special protections for inmates based on gender expression, gender identity, and sexual orientation. The Executive Yuan commissioned research that produced a draft proposal recommending that "correctional facilities arrange housing according to an inmate's gender identity." The Ministry of Justice's response to both: handle each case individually.
There is a notable exception. Taiwan has explicit rules for the short-term detention of foreign nationals and residents from Hong Kong and Macau, who may be housed individually based on the sex listed on their documents or a diagnosis of gender dysphoria. For the criminal detention of its own citizens, no comparable framework exists.
The practical stakes are real. Taiwan currently requires surgery before a person may change the sex marker on their national identity card. Transgender inmates who cannot or do not wish to undergo surgery are therefore assigned to facilities that do not match their presentation, exposing them to elevated risks of discrimination and violence. Extended solitary confinement can shield an individual from immediate harm but effectively cuts them off from the social interaction necessary for eventual reintegration into society.
What Japan's Timeline Suggests for Taiwan
Japan's own experience offers a sobering timeline. From the first major public controversy over transgender detention in 2001 to the Ministry of Justice's administrative guidelines in 2011 took a full decade of litigation, petitions, and public debate. New legal challenges continued to emerge after 2016, and researchers note that the underlying questions remain unresolved to this day.
Japan has still not written transgender detention policy into law. Its existing guidelines continue to use family register sex as the primary basis for housing decisions, leaving the system ill-equipped to handle every individual situation.
In Taiwan, the Ministry of Justice has responded to legislative resolutions and academic proposals alike with the same formula: handle it case by case. Scholars who have studied the issue have been direct in their assessment. The Ministry's posture, one researcher concluded, is "deeply troubling."
*Source: Chiang Yu-nu (江玉女), "Japan's Prison Criminal Policy Toward Transgender Inmates," Japan and Asia-Pacific Studies Quarterly, JaQ, Vol. 10, No. 1 (January 2025).*
