Transgender activists are targeting companies which advertise on Mumsnet, because the online forum allows people to debate transgenderism.
Mumsnet founder Justine Roberts said she had been approached by three significant advertisers who had been contacted by pro-trans groups threatening boycotts.
Roberts said: “What’s worrying to me is the thought-police action around speech and the shutting down of the right to be able to disagree and immediately labelling it as transphobic”.
She added that there is “a section of the hardline trans side which thinks that any discussion at all is by definition transphobic”.
Mumsnet, Britain’s most popular parenting website with twelve million monthly users, does not take a position on the debate, but its founder is determined to protect free speech.
The activists, she said, demonise anyone critical of the self-identification plans by portraying them as evil bigots who want to eradicate transsexuals and incite violence against them.
She concluded that proper debate is essential, as “what is proposed is nothing less than changing the very definition of man and woman in law – biology replaced with identity”.