“Mumsnet did not set out to change the world or engage in an overtly political way,” its founder Justine Roberts tells me. “The opportunities came about because our users are so engaged and passionate.” Mumsnet’s first web chat with a major politician was with then-opposition leader David Cameron in 2006. Now, Roberts explains, “it’s become a bit of a rite of passage for any self-respecting senior politician.”

In September, with the Labour Party under increasing strain on issues such as Brexit and antisemitism , British Shadow Chancellor John McDonnell sat down for one of his widest-ranging and toughest interviews yet. Instead of senior political journalists, however, his interrogators quizzed him from behind screens across the UK through a website known as Mumsnet.

Roberts credits its membership with the growing influence of the site. “When our users saw that their voice was regarded as important and useful, they asked us to use what clout we collectively had to drive campaigns on issues such as rape myths, miscarriage care, and the treatment of children with disabilities and special educational needs.”

In its early days, Mumsnet operated as a one-stop-shop for mothers. Amongst discussions about the practicalities of motherhood, childcare, support for disabled children, and a range of other topics, Mumsnet was most likely to hit headlines for the likes of the infamous "penis beaker” thread , which gained internet notoriety when a user asked for views on her post-sex cleanup arrangements.

Eighteen years on, though, the community is more likely to be referenced as both a significant mainstream political force and a touchstone for anti-trans sentiment and organizing in the UK. These two aspects of the social network may seem utterly contradictory, but closer analysis of its history and user demographics suggest that the two actually serve to complement each other.

Since its conception as an online parenting network in 2000, Mumsnet has grown to boast over 10 million users and an annual turnover of £7.2 million. It continues to grow its users by 13 percent each month and has been referenced in Parliament, as well as hosting web chats with figures such as Hillary Clinton and then-prime minister Gordon Brown.

Sarah Pedersen, professor of communications and media at Robert Gordon University, has carried out extensive research into Mumsnet. “The influence stems from the type of woman it attracts,” she tells me. “Research shows it has an overall middle-class demographic: a high percentage of its members are graduates and working at least part time outside the house.

But if, as Roberts and Pedersen assert, the community’s influence is a result of its engaged membership, Mumsnet finds itself at the political whims of a very particular membership base. When it comes to Mumsnet’s reputation for transphobia, it seems that the very demographics to which Pedersen attributes its success may have resulted in an especially narrow vision of womanhood—one that specifically excludes trans women.

Mumsnet has led a number of successful campaigns: its 2010 ‘Let Girls Be Girls’ campaign against the sexualization of children saw recommendations incorporated into a government review, and the ‘Let Toys Be Toys’ campaign in 2016 garnered widespread support in its fight against gendered toys.

The range of experience of members is amazing—journalism, PR, law, government and business leadership—which means different groups of members are able to quickly organize and campaign on particular issues.”

Since 2016, Mumsnet—specifically its Feminism board—has increasingly found itself on the receiving end of criticism from trans people and their allies. “When I started using Twitter and engaging in the trans sphere in mid-2017, Mumsnet was constantly referenced both on my timeline and in DMs,” says Joss Prior, a trans woman who is part of a sizable trans community that monitors and discusses Mumsnet regularly. “The whole of the Feminism board was like a spectre hanging over the daily trans discourse.”

Prior points to the now partially-deleted but notorious 2016 “I Am Spartacus” thread in which a user asserted that “men cannot become women, ever. Women cannot become men, ever” and went on to misgender a number of trans men and women, including high-profile campaigners Paris Lees and Danielle Muscato. The post sparked thousands of supportive comments and is consistently referenced in up-to-date threads, with “I am Spartacus” acting as a shorthand rallying call for anti-trans feminists. Attempts have even been made to organize campaigning activity around the phrase.

In March of this year, Mumsnet was used to organize against Girlguiding’s trans-inclusive membership policy in collaboration with anti-self identification campaign group Fair Play For Women. Users also responded to Gender Recognition Act proposals that would allow trans people to self-identify with protests such as Man Friday, a campaign that encourages cis women “identify as men on Fridays" and partake in male behaviours like “manspreading and mansplaining” or to access single sex male spaces such as changing rooms, swimming facilities, or sports clubs.

“It’s a core group of a few hundred hardcore trans-exclusionary radical feminists (TERFs), a tiny percentage of overall users,” says Christine, the mother of a trans child and also part of the network that regularly monitors Mumsnet. (Christine’s name has been changed for privacy reasons.) “Yet the Feminism board is just 90 percent discussions about trans people on any given day.”

A search of my own name returns a post calling me “a witless handmaiden” for supporting trans people on Twitter.

Testing this out across four consecutive days, I found threads about trans rights and related topics to consistently dominate the Feminism board, with new threads appearing more than hourly and the handful of unrelated topics receiving only a fraction of the same engagement in terms of comment numbers. Topics during this time included discussions about specific trans campaigners, gender reassignment surgery for children, and the now-closed Gender Recognition Act consultation. Searches for the names of high-profile trans women throw up many instances of deadnaming and misgendering amid sometimes intensely personal insults. A search of my own name returns a post calling me “a witless handmaiden” for supporting trans people on Twitter.

In March of this year, former intern Emma Healey publicly criticized the site’s stance on trans rights and shared private internal communications on the subject. Healey alleged that the “vast majority” of trans discussion on Mumsnet “descends into scaremongering and hate speech,” claiming that the company dismissed staff concerns about the offensive tone of the posts. In April, former Mumsnet employee Hannah Woodhead wrote in Huck magazine: “The anti-trans community on Mumsnet is something of an open secret. It has been present for years, and it appears that there has, for a while, been a lax approach to tackling this particular form of hate speech.”

Prior argues that Mumsnet has been hijacked by anti-trans campaigners as a safe space for organizing, rather than the sentiment having grown organically through its original base. “As one of the few popular sites still pushing out-of-date 70 and 80s rhetoric, it became a beacon and attracted more and more people looking for confirmation bias,” she says. “I don’t think [transphobia] was ever the starting point for Mumsnet, merely an inevitable consequence of the people and rhetoric they uphold.”