My hope for a more open discussion of women’s and trans rights is fading

I would like to suggest that the response to last week’s protests against philosophy professor Kathleen Stock at the University of Sussex could mark a turning point in the argument over women’s and trans rights that has become one of the most contentious political topics. After activists put up posters calling for her to be fired, and displayed a “Stock Out” sign on campus, the university’s vice-chancellor was among the prominent voices who spoke out in her defence.

But although this is tempting, especially to a gender-critical feminist like me who shares Stock’s perspective, it would be foolish. That’s because the gap dividing the protesters’ views from those of leading politicians is not very large. This might sound over-the-top. Neither Keir Starmer nor any other leader has called for women to be sacked because they don’t share trans activists’ objectives, such as the law reform known as self-ID, which enables people to change their legal sex without a medical diagnosis.

But Starmer’s recent comments on the Andrew Marr Show, along with remarks by the new Green party co-leader Carla Denyer, make it clear that they too believe that gender-critical feminists’ ideas are beyond the pale. Asked by Marr whether it is transphobic to say that only women have a cervix, a reference to a comment made by Labour MP Rosie Duffield last year, Starmer replied: “It is something that shouldn’t be said. It is not right.” Not only does Starmer disagree with Duffield’s use of the word “woman” to refer to biological sex rather than gender identity; he thinks women who hold such views should keep quiet. Denyer, meanwhile, called the gender-critical gay and lesbian rights charity LGB Alliance a “hate group”.

Such illiberalism is all the more disappointing because after years of polarisation I had become hopeful that a more open discussion about sex and gender might start. This optimism was mainly due to a recent court case. For a year and a half until this summer, anyone who wanted to denounce a gender-critical feminist only had to reach for the words of Judge James Tayler. At an employment tribunal in 2019, he ruled that the gender-critical belief held by Maya Forstater was “incompatible with the human rights of others”, “absolutist” and “not worthy of respect”. But in June this year a higher court overruled him when it decided that the belief – summarised by Mr Justice Chowdhury as a belief that “biological sex is real, important, immutable and not to be conflated with gender identity” – is protected as a philosophical belief in UK law.

Related: University defends ‘academic freedoms’ after calls to sack professor

A further hearing will decide whether Forstater was discriminated against when her contract with the Centre for Global Development was ended after colleagues accused her of transphobia. But either way, the granting of protected status to gender-critical belief should have opened up space for a negotiation. What happened instead is that opponents doubled down. In June, Stonewall’s chief executive Nancy Kelley likened gender-critical ideas to antisemitism. Last month the US philosopher Judith Butler lumped them in with the “anti-gender ideology [that] is one of the dominant strains of fascism” in a Guardian interview (amended after publication because one of the questions risked misleading readers about an alleged crime).

A few days later Mridul Wadhwa, head of Edinburgh’s Rape Crisis Centre, echoed this by saying that opponents of self-ID are “very comfortable associating with fascists”. Such was the hostility aimed at Duffield that she decided not to attend her party’s conference – and went to an unofficial feminist fringe meeting instead. Then came the protests against Kathleen Stock.

None of this is new exactly. Over recent years, women with views like mine have routinely been described as hateful. This happened even when we made it clear that we oppose bigotry and support laws protecting transgender people from discrimination. But what is shocking is the escalating language and threats, to the point where Stock – the author of a well-reviewed book on this subject – was advised by police to install CCTV.

For the avoidance of doubt, I appreciate that for transgender people it is vital to be accepted in the gender to which they have transitioned. I know that this is what the statements “trans men are men” and “trans women are women” mean. I also think it is vital to have words that refer to people’s sex. Of course, it is true that trans men have a cervix and in that sense Duffield’s remark was inaccurate. But it’s also true that for many people, the words “man” and “woman” signify biological sex. And this linkage cannot be severed by diktat.

In some ways the debate has progressed. New evidence-based guidelines from the UK sports councils, for example, explain that there is no simple way to balance inclusion with fairness. Sporting bodies are encouraged to seek “fresh” answers. There is also growing recognition that while inclusive language is important, the “gender-neutral” terms that emerge from such efforts can be dehumanising and inappropriate. When the Lancet recently described women as “bodies with vaginas”, a range of people objected.

On single-sex spaces, though, there is little sign of a breakthrough. Trans activists argue that to question the inclusion of trans women in female prisons, refuges or changing rooms is to engage in a “moral panic”. Gender-critical feminists (who, it should be noted, also disagree among themselves) counter that the wish for female-only spaces is reasonable, and the fear of male abusers who could take advantage of self-ID rules is rooted in fact. While non-binary, genderfluid and other trans people – such as the police officer recently issued with warrant cards under male and female names – may benefit from a situation in which boundaries are porous, letting them escape constricting gender roles, other people prefer the separation of the sexes in some places (such as where people are undressed) to be unambiguous.

Behind such practical considerations lie philosophical ones. It seems easy, for some, to dismiss any resistance to changing cultures of gender as reactionary (or quasi-fascist). It is true that most of the MPs speaking up for Kathleen Stock so far have been Tories. By not explicitly condemning the demands for her to be sacked, while calling for an “investigation” into “institutional transphobia”, the academic union, the UCU, appeared to side with the campaign against her.

But it is a mistake to imagine that the only people for whom sexual differences are meaningful are evolutionary biologists or religious conservatives. For gender-critical feminists, our politics are underpinned by an analysis of the way female bodies and reproductive labour have historically been controlled and exploited. This is why we describe women’s rights as “sex-based”.

In common with others, including the philosopher Jane Clare Jones, I also see a connection with the environment. I think there are parallels between the failure to address the implications of our planet’s finite resources and our dependence upon it, and the idea that human potential is boundless. While I want people to be free to live as they choose, I also believe that human bodies have limits. And I am concerned about the influence on young people of the idea that, with the aid of medical technology, these can be transcended.

It seems clear that investigations of gender have a long way to go and my own understanding is neither fixed nor complete. I don’t expect most people to agree with the thoughts I have set out above and know that some will strongly object. I know too that for some people their gender identity – the feeling of being male or female – means more than chromosomes or anatomy. I want to find a way for our different ideas to coexist. But I am very worried by the lack of an equivalent recognition of gender-critical beliefs. And I think the most recent round of attacks on feminists should alarm everyone who cares about pluralism.

• Susanna Rustin is a Guardian leader writer