So, First Minister, do you think a woman is an adult human female?

That is, of course, the dictionary definition of a woman. It is also a proposition that 99 per cent of British voters would see as wholly unobjectionable, indeed, self-evident. Obviously a woman is female. So why could Mr Davey not answer, and why, indeed, was a LibDem party member, Natalie Bird, banned from standing as an MP because she wore a tee shirt with this dictionary definition on it? Why has the Labour MP, Rosie Duffield, been forced to avoid the Labour Party conference on safety grounds for agreeing?

Earlier this year, the SNP's elected Equalities Convener, Lynne Anderson, and its Women's Convener, Caroline McAllister, both resigned over the definition of a woman. The Green Party has also split from top to bottom with departures and resignations, including that of the much-respected former Scottish MSP, Andy Wightman who said he couldn't stay in a party that refused to discuss women's sex-based rights. The UK Green Party co-leader, Sian Berry, resigned apparently because there was too much discussion of women being female.

Like Ms Berry, Mr Davey was trying to keep on the right side of the transgender debate by not deviating from the Stonewall mantra: “transwomen are women”. He appears to believe that this means it can never be assumed that a woman is actually female. Indeed, a “woman” could be someone who was born a man and has transitioned to female. But this involves an excruciating logical contortion. Why, if a transgender woman is literally a woman, should it not continue to be the case that a woman is an adult female? Hapless politicians like Mr Davey have been forced into holding a proposition which is manifestly absurd: that women are not adult human females but transwomen always are.

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Mr Davey's predecessor, Jo Swinson, got into similar difficulties. During the General Election campaign she dissolved when asked by a BBC presenter whether babies were born male or female. After much faltering and deviation, she said she didn't think they were and that they might be “non-binary”. Labour's then Shadow Secretary for Women and Equalities, Dawn Butler, went further and asserted that “a child is not born with a sex”.

Both of them were basing this on the assertion by transgender activists that sex is “assigned” at birth and not observed. This has become an article of faith in the rarified world of non-binary theory, as expounded by the American gender philosopher, Judith Butler. She says sex is a social construct. Or to be precise: "sex is an ideal construct which is forcibly materialised through time. It is not a simple fact or static condition of a body”. Butler is herself non-binary and insists on being called “they”– which means they is always referred to in the plural.

Make of they's definition what you will, but it doesn't exactly make for a snappy sound bite. Most voters would prefer not to be bothered with incomprehensible structuralist jargon. But they are going to be very bothered indeed if they keep hearing party leaders, like Ed Davey, dissolving into confusion when asked whether a woman is an adult female.

Ed Davey with Andrew Marr

This, of course, has been brought to a head by the row over transgender self-ID, which is coming soon to a parliament near you. One of the key planks of the Green-SNP alliance is a new law saying that, since transwomen are women, they should be permitted to change their legal sex merely by giving a declaration of such. No medical intervention, surgery or lengthy record of living as a woman is necessary.

This is presented as merely a means of simplifying the bureaucratic process of achieve gender reassignment, changing legal sex, which has of course been the law since 2004. But many women, sometimes called “gender-critical feminists” (or “fascists” according to Judith Butler), do not accept that it is or should be legal for people born male to be allowed to enter women's spaces like changing rooms, prisons, or women's refuges. Many say they feel threatened by the presence of male-bodied individuals.

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People may be surprised at how far down this road we've already gone. The CEO of Edinburgh Rape Crisis, Mridul Wadhwa, was born a man. Prisons are now legally obliged to place male-bodied transgender offenders in women's prisons. Schools are being told to use gender-free pronouns and recognise primary children as transgender whatever their parents may think. Women are often now referred to as “persons with a cervix” or “menstruators” by medical professionals who fear that they might fall foul of the 2010 Equalities Act in which “transgender reassignment” is deemed to be a “protected characteristic”.

But the trouble with the Equalities Act is that it says a lot of things, most of them mutually contradictory. Sex is also a protected characteristic under the legislation, a whole section of which specifically refers to “single sex services” being a “legitimate aim”. A legitimate example given is a transwoman being excluded from counselling group of female victims of sexual assault.

Stonewall says that women do have a right to single sex spaces but do not have a right to exclude transwomen from them, because such exclusion would be discriminatory under other provisions of the Act. This abstruse legal argument used to be very much on the fringes of political life. But it is about to become centre stage. Nicola Sturgeon says she has found a way of achieving self-ID without diminishing women's sex-based rights. Good luck with that. We'll know if and when she agrees that a woman is an adult human female.

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