This post is part of Outward, Slate’s home for coverage of LGBTQ life, thought, and culture. Read more here.

Author J.K. Rowling is in hot water with many fans. On Thursday, the Harry Potter creator tweeted her solidarity with Maya Forstater, a British woman who was let go from a think tank position for anti-trans statements and earlier this week lost a lawsuit against her former employer. Many Americans seem to feel shocked and betrayed by Rowling, who had become a political icon of sorts because of her liberal stances. But in truth, Rowling’s apparent support for anti-trans positions is in line with that of many U.K. liberals, an indication of how mainstream anti-trans attitudes in the U.K. have become. The situation here in the U.K. has grown so toxic, in fact, that in 2017 New Zealand provided residency on exceptional humanitarian grounds to a trans woman from the U.K. on the basis of the persecution she faced for her gender identity.

The Forstater case hits at the heart of trans discourse in the U.K.—a discourse that centers on the importance of sex in navigating inequality and that looks remarkably different from that in America. After her contract with the Center for Global Development was not renewed on the grounds of her anti-trans comments, Forstater took her case to an employment tribunal for wrongful termination. She argued that she was discriminated for “philosophical beliefs.” This “gender critical belief” included the idea that trans women are not women because they are not of the female sex. On Wednesday, the court rejected her case, finding that that her opinion of the importance of sex in recognizing gender was not a philosophical belief and, as such, did not deserve legal protection.

Key to this debate is understanding notions of sex and gender, so let’s briefly review. Sex is understood as biological, often considered chromosomal or anatomical. Gender is understood as a cultural construction of identity, often associated with one’s sex. Many assume sex to be a binary: male or female. Yet scientists have long recognized that there are more than two sexes: Intersex people, for example, are those born with chromosomal, anatomical, and hormonal characteristics that are “in-between” what most people would consider the binaries of sex. (And for the record, they are as numerous in the world as people born with red hair.)

Historically, mainstream Western conceptions of gender were also binary: man or woman. Gender nonconforming (or gender nonbinary) people challenge this gender binary. People whose gender identity does not match their sex assigned at birth are known as transgender. (People whose gender identity does match their sex assigned at birth are known as cisgender.) While trans and gender nonconforming people have always existed, their prominence in broader Western public consciousness is recent. Time famously declared “the Transgender Tipping Point” in May of 2014.

Trans people face oppression just about everywhere, including in the U.S. They are subject to extraordinary violence (at least 24 trans women have been murdered this year in the U.S.), societal discrimination, and strong currents of transphobia, notably encouraged by the Trump administration. However, the broader U.S. public discussion, especially in progressive circles, has moved away from questioning the legitimacy of trans identity. Prominent U.S. feminists and LGB advocates have stood in solidarity with trans people. And there’s been recognition that feminism is trans-inclusive. Unfortunately, in the U.K. this has not been the case. Here, trans people not only experience violence and discrimination, but are subject to toxic public discourse harbored well within the mainstream.

Though simmering for many years, the current wave of anti-trans rhetoric erupted in 2017. That’s when the British government opened consultations on proposals to change the Gender Recognition Act, a 2004 law that establishes how trans people can change the gender on their government documents. LGBTIQ rights organizations such as Stonewall advocated for an amendment to the act, which would ease the associated administrative burdens. Opponents of trans rights were concerned that this law relaxed the process too much.

To challenge Stonewall, the organization Woman’s Place U.K. was formed. Composed of prominent Boomer-generation feminists and lesbian activists (often labeled trans-exclusionary radical feminists, or TERFs), the organization launched itself on the basis of defending cis women. Like U.S. “bathroom bill” proponents, Woman’s Place U.K. argued that accepting trans women as women placed cis women at risk. This risk was physical, in terms of safety in single-gender spaces, as well as more structural, in terms of data collection and government statistics. The assertion was that incorporating trans women into the concept of women might lead to less government attention on cis women. The organization’s stance has been criticized for a flawed argument while ignoring the extreme vulnerability of trans people. It also was critiqued for ignoring cases where spaces for vulnerable women successfully opened themselves to trans women, as well as studies that indicate that trans-inclusivity does not negatively impact cis women. Nonetheless, the debate continued, with even the Guardian U.K. backing the “inequality is biological” argument—a move their U.S. colleagues felt it necessary to protest.

To locate the origins of the U.K.’s particular flavor of transphobia, we need to examine the term “trans-exclusionary radical feminist.” Leaders of this movement are indeed radical feminists, including Germaine Greer. Although widely misused as a disparaging term, radical feminism is a submovement of second-wave feminism, which argues for the recognition of the difference between the sexes rather than the equality of the sexes. Greer argued in her 1999 book The Whole Woman that recognizing this difference would provide a liberation that would let women be “free to define their own values, order their own priorities and decide their own fate.” Radical feminism differs from the “equality feminism” that dominates in the U.S., summarized by Merriam-Webster as “the theory of the political, economic, and social equality of the sexes.”

By centering sex in their conception of womanhood, opponents of trans equality argue along the lines of Forstater’s claim that trans women are not women because they are not female. In doing so, opponents of trans rights dehumanize trans people by questioning the legitimacy of their gender identity, passively reinforcing the belief that trans identity is a mental illness. In the U.K., trans people and their allies have completely rejected any conversation around legitimacy because they believe that one should not have to defend one’s identity or existence. They have begun a practice of “no platforming,” where they protest universities and other institutions giving trans rights opponents the position to promote transphobia. Universities have thus become major battlegrounds for this debate, where professors have argued that being forced to create a welcome environment for trans students impedes their academic freedom.

The British argument that trans recognition and equality are a threat to cis women is unfortunate. Assuming a winner-takes-all approach does not correspond to reality. By homing in on a fault-prone biological argument and creating this false distinction, British opponents are enabling a violent discourse that exacerbates the vulnerability of trans people. Moreover, they are missing the point that cis women and trans women face many similar hardships. Of course, their experiences may be different, but the trans rights movement does not require that trans women and cis women be considered the same; it requires instead the recognition that both are women—women who are negatively affected by misogyny and societal expectations of gender. Acknowledging that trans women are women does not undermine the experiences of cis women; it instead brings together a broader coalition of those demanding freedom and safety for all.