Differing attitudes to women’s and transgender rights activism are often said to be generational. One poll, published a month on from the supreme court ruling that the legal definition of “woman” in the Equality Act is based on biological sex, found 63% supportive of the ruling and 18% opposed. But younger people were far more likely to be in the latter camp, with 53% of 18- to 24-year-olds disagreeing with the judgment. In my age group, 50-64, the figure was just 13%. Such results echo earlier polls.

As with any attempt to link a demographic with a point of view, there are plenty of exceptions. Last month Lady Hale, the octogenarian former president of the supreme court, became one of them when she argued that the ruling had been misinterpreted, telling a literary festival she had met doctors “who said there is no such thing as biological sex”.

The progressive explanation for the age gap is in the name: progress. As the arc of history bends towards justice, younger people are ahead of the curve. Social scientists call this a cohort effect, which basically means that when you are born is one of the influences (along with income, education and so on) on your politics. In relation to transgender rights, the reasoning is that people born since the 1980s are more relaxed about sex and sexuality, and more committed to personal freedoms including the right to define one’s own identity. The obvious catch to this analysis, at the moment, is the way some young men have swung towards the hard right.

If a cohort effect applies when it comes to gender, and assuming that future cohorts are in agreement, gender identity advocates can look forward to winning this argument eventually. Older, conservative voters (and politicians and judges and journalists such as me), who don’t think someone’s trans identity should take precedence over their biological sex when society decides which sports teams or prisons they belong in,........

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