The Society for Evidence-Based Gender Medicine (SEGM) is an anti-trans organization that is known for its opposition to gender-affirming care for transgender youth and for engaging in political lobbying. SEGM is known for transgender health care misinformation. It has falsely claimed that the majority of transgender children desist, argued that gender exploratory therapy should be the first line treatment for those under 25, and promoted the scientifically unsupported theory of rapid-onset gender dysphoria. SEGM is often cited in anti-transgender legislation and court cases, sometimes filing court briefs.
SEGM is closely affiliated with Genspect and Therapy First. Seven advisors to SEGM are on Genspect's team of advisors, including Stella O'Malley, Genspect's founder. The Southern Poverty Law Center has designated SEGM and Genspect as anti-LGBTQ+ hate groups since 2023 and described SEGM as "a hub of pseudoscience". Researchers at the Yale School of Medicine issued a report which described SEGM as a small group of anti-trans activists and not "a recognized scientific organization". A spokesperson for the Endocrine Society described them as outside the medical mainstream. A paper published in March 2024 described them as a "fringe medical organization".
Leadership and founding The Society for Evidence-based Gender Medicine (SEGM) was founded in 2019 as an international group of clinicians and researchers. Its co-founders include William Malone, an American endocrinologist; Julia Mason, an American pediatrician; and Zhenya Abbruzzese, an American healthcare researcher. Psychiatrist Stephen B. Levine, who has testified in nearly every case on gender-affirming care in the United States and argues transgender people become pathologically narcissistic, is an advisor. SEGM, among other affiliated groups, was formed through connections in the "Pediatric and Adolescent Gender Dysphoria Working Group", a group of 17 academics and researchers including Kenneth Zucker, Ray Blanchard, and J. Michael Bailey. Several SEGM members collaborated with the CAMH Gender Identity Clinic which was directed by Zucker.
A report by the Southern Poverty Law Center described SEGM as a hub of the "anti-LGBT pseudoscience network", and specified that the relationship was strongest between SEGM, Genspect, and Therapy First, who shared over 24 personnel connections. The report also stated SEGM members are affiliated with the "anti-LGBTQ+ far right". Julia Mason, Marcus Evans, Roberto D'Angelo, Sasha Ayad, Stella O'Malley, Lisa Marchiano, and Avi Ring are advisors for SEGM and are on Genspect's team or advisors; O'Malley is the founder of Genspect. Therapy First is a group of therapists founded in 2021 by four SEGM members and a Genspect advisor to market, gender exploratory therapy, which experts believe is transgender conversion therapy. Marchiano and O'Malley are on the board of Lisa Littman's Institute for Comprehensive Gender Dysphoria Research (ICGDR). SEGM members O'Malley and Robert P. George are also advisors to the Foundation Against Intolerance and Racism.
A report by seven people in various departments of the Yale School of Medicine stated that the 14 core members of SEGM regularly worked together on the boards of other organizations that oppose gender-affirming healthcare and "feature biased and unscientific content."
Activities Advocacy and legislative activities SEGM funds systematic reviews, organizes academic events, and occasionally submits positions to courts and lawmakers. Yale University's Integrity Project estimated that 75% of SEGM's publications are letters to the editor and comments, as opposed to peer-reviewed scientific articles. SEGM frequently testifies in state legislatures in favor of anti-trans laws.
South Dakota House Bill 1057, which was launched in 2020 to prohibit gender-affirming care for transgender youth, relied on a document created and distributed within a secret working group including multiple members of the American College of Pediatricians (ACPeds), representatives from other conservative groups, and founders of SEGM. SEGM members have repeatedly co-authored papers and letters to the editor with members of ACPeds. SEGM director Julia Mason tweeted that SEGM would not work with members of ACPeds and denied knowing ACPeds member Paul Hruz despite co-authoring papers and co-hosting symposia with him. ACPeds has explicitly promoted the work of SEGM; Quentin Van Meter encouraged audience members to work with SEGM at a conference held by "ex-gay" ministry First Stone Ministries.
SEGM made a submission in defense of the state of Arizona's ban on Medicaid coverage for transgender healthcare. Lambda Legal and Cooley LLP filed an amicus brief opposing the ban on behalf of LGBT advocacy organizations such as PFLAG. The Pediatric Endocrine Society and the World Professional Association for Transgender Health also filed amicus briefs opposing the ban. SEGM members also contributed expert defense testimony to Florida's ban on medicaid for transgender healthcare.
In March 2022, Julia Mason, a board member of SEGM who also works with Genspect, proposed Resolution 27 along with four other members of the American Academy of Pediatrics (AAP), stating the AAP should reconsider hormone therapy as a first line of treatment and called for an evidence review to update AAP's 2018 policy statement on gender affirmative care. The AAP said that the resolution mischaracterized its policy, which instead promotes "following a systematic, collaborative evaluation by clinicians and mental health professionals". The resolution was not passed. After the resolution's proposers said that the AAP changed procedures to block discussion of the resolution, the AAP said that their processes worked normally and that Resolution 27 did not pass because it received no co-sponsorship and the majority of AAP members did not agree with the resolution. The AAP stated the guidelines were already under review as part of a routine procedure and that "there is strong consensus among the most prominent medical organizations worldwide that evidence-based, gender-affirming care for transgender children and adolescents is medically necessary and appropriate".
In April, the Florida Department of Health wrote a memo which misrepresented the scientific consensus to stop minors in the state from socially or medically transitioning and cited Malone. The same month, SEGM met with White House officials in the Office of Information and Regulatory Affairs to argue that a rule on "nondiscrimination in health programs and activities" from the Department of Health and Human Services' Office for Civil Rights would "effectively force physicians to provide hormonal and surgical interventions".
In September 2023, SEGM members and advisors filed a petition with the U.S. Food and Drug Administration calling for them to end prescriptions of puberty blockers to transgender youth. SEGM claims to have over 100 members but removed their membership list and organizational structure from the site in late 2023.
In 2025, SEGM co-founder Zhenya Abbruzzese co-authored the Trump Administration's HHS report on gender dysphoria.
McMaster University systematic reviews Between 2021 and 2024, SEGM gave a team at McMaster University headed by Gordon Guyatt, a pioneer in evidence-based medicine, $250,000 to conduct independent systematic reviews into trans healthcare. SEGM was involved in choosing the question for each of the reviews. The reviews were published in 2025. The reviews "graded the evidence for each intervention as having either low or very low certainty." Following their publication, the studies received criticism from people who questioned their veracity due to SEGM's involvement.
The results of the reviews were quickly seized by anti-trans activists, right-wing news outlets and the Trump Administration to justify questioning and restricting gender-affirming care. Guyatt claimed he had written to several news outlets that prominently cited the reviews to tell them "You are misconstruing how my work should be interpreted and used". However, all of the outlets refused to publish his letters.
In July 2025, an opinion piece by professors at the university called on the university to distance themselves from the reviews. In August 2025, Guyatt and his team released a statement asserting that using the reviews to deny care was a "gross misuse of our work and is unconscionable" and that while SEGM initially "appeared to us as non-trans, cisgender researchers to be legitimately evidence-based", they would no longer work with them in the future. The statement continued to say it was "profoundly misguided to cast health care based on low-certainty evidence as bad care or as care driven by ideology", with Guyatt saying "low quality evidence doesn't mean it doesn't work. It means we don't know." Guyatt additionally criticized anti-trans activists for using the report to claim that is it unknown if anyone benefits from gender-affirming care, saying that whether some people are harmed by gender-affirming care is just as unknown, but that due to the testimonies of people who have undergone the treatments, there is "sufficient evidence to say there are some people who are benefited".
Conversion therapy
The Trans Safety Network stated "SEGM's public members include ... outspoken critics of regulation against conversion therapy on transgender people." The SPLC has stated SEGM is part of a network of groups which "support conversion therapy for transgender people and banning medical transition, beginning with people under age 25".
SEGM submitted a brief on a proposed amendment to a Canadian criminal code outlawing conversion therapy, attempts to change gender identity or sexual orientation. SEGM stated that "There is a very real risk that all forms of supportive and explorative psychotherapies for young patients who present with gender dysphoria will be classified as 'conversion, and justified their position by claiming that conversion therapy can only be applied to lesbian, gay, and bisexual people, a position not supported by any major medical organization.
Positions SEGM advocates for psychotherapy, including exploratory psychotherapy, as the first-line treatment for those age 25 and under, even though evidence does not support it. SEGM no longer believes medical interventions to be appropriate at any age. Malone has opposed the informed consent model for transgender healthcare, where adults older than 18 can start hormones after signing an informed consent document without requiring an evaluation by a mental health professional.
SEGM believes that psychological support should be offered as an alternative treatment and cites health policies in Sweden, Finland and the U.K as supporting this, though evidence for psychotherapy as a treatment for gender dysphoria is weak.
SEGM has advanced the controversial idea of rapid-onset gender dysphoria (ROGD), which suggests a subtype of gender dysphoria caused by peer influence and social contagion. ROGD has been described as lacking evidence or sound empirical studies by the majority of major psychological bodies in the USA.
Citations in anti-trans legislation Proponents of gender-affirming care bans often cite letters to the editors of scientific journals from leaders and members of SEGM Multiple letters were co-authored by SEGMs board secretary since inception, William J Malone, and members of the American College of Pediatricians such as Quentin Van Meter, Paul Hruz, and Michael Laidlaw.