Just for the record, she says: “I am not against there being trans women, or even a gender-recognition act, I’m just against it being based on self-identity and how you feel. There should be meaningful gatekeeping. You should have to have a diagnosis and you should have to demonstrate commitment and there should be gender dysphoria. It should be a therapeutic last resort rather than the thing a four-year-old does when he likes pink.

“In some university campuses we have posters in women’s toilets which say that if someone comes in to the bathroom who is a gender you don’t expect, or who looks like they are using the wrong bathroom trust them, not you [ie not your own instinct]. The norm we have is being eroded so we won’t be able to challenge anyone who comes into a bathroom, dormitory or changing room.”

At the same time, ideas about gender fluidity are percolating into the mainstream. Only last week, a BBC film featuring children aged 9-12 and made to support the personal, social and health education (PSHE) curriculum in schools claimed there could be more than 100 “gender identities”. Facebook currently lists more than 70, including two-spirit person, polygender, intersex man, genderqueer and cis.

In Stock’s view, this makes very little sense. “To say there are more than 100 genders is confused. If this was just going on in some ivory tower it wouldn’t matter, but it’s being disseminated in schools and children can’t possibly understand other than in very simplistic terms: a girl who likes playing with cars and maybe fancies other girls may well conclude the teacher is telling her that she’s really a boy and that has serious potential consequences.”

The number of young people questioning their gender is on the rise: the Tavistock and Portman NHS Foundation Trust received 2,519 referrals to its gender identity development service in 2017-18. “There’s been a spike in young, teenage girls transitioning,” says Stock. “When they get to 25 they might feel differently, but by then they’ve got physical traces on their bodies caused by the drugs and they may well be infertile. Doctors aren’t tracking them, there aren’t any psychological programmes for them, they’re sort of in limbo…

“There’s a growing number on social media and they are often very intelligent, articulate, sensitive people, well able to analyse their own situation. I just hope academics will attend to that phenomenon socially, psychologically and medically because it’s going to be increasingly important. What’s emerging is lack of understanding of the impact of puberty blockers on young bodies. None of that can be talked about, it’s “transphobic”. You can’t question a child or it’s ‘conversion therapy”.

“We have to talk about all this.”

She’s right - but in the current climate, who will be brave enough to speak out?