When does an apparently persecuted minority become a persecutor? Is it when its cause is appropriated by those with their own political agenda?
Or when, having won a few precious rights, it feels the need to guard against losing them again, whether or not they are under threat.
Welcome to the transgender debate, which has grown so toxic that merely raising the subject risks a metaphorical brick through the window.
Anyone who dares to question the orthodoxy of transgender activism is shouted down in a campaign of intimidation that has got completely out of hand.
The majority of people in this country are broadly tolerant of diversity in all its forms and fiercely protective of free expression (in gender, religion, politics, culture).
But the emergence in recent years of a trans lobby, self-appointed to judge what the rest of us can think or say and mete out punishments accordingly, has, I suspect, made the public less, not more supportive of individual differences.
I’m not planning on reading any online comments this column might attract (I never do, anyway), so will brave the minefield of the “trans war” raging in Scotland right now.
Far braver than me, though, are the women who have led the pushback against a movement that would undo the hard-won liberties of female emancipation.
These are not transphobic reactionaries, but outspoken feminists, largely on the left, who fear the consequences of gender fluidity without medical diagnosis.
Joan McAlpine, the SNP politician, has attacked her party’s plans to make it legal for men to “self-identify” as women, or vice versa, a measure that has been backed by First Minister Nicola Sturgeon.
Under the existing Gender Recognition Act of 2004, people who want to transition to a different gender have to provide medical evidence of their distress, show they have lived as the opposite sex for at least two years, and formally commit to their new gender for life.
But the SNP’s proposals will do away with such safeguards and, said McAlpine, enshrine in law “the process of pick your own sex”.
She has voiced concerns that, with the new rules, women-only spaces, such as changing rooms, women’s refuges and care facilities, would be accessible to predatory men, as well as harmless trans people. She highlighted the case of a male sexual offender abusing their position as a transgender woman to carry out further attacks.
Her fears seem justified, given that some police forces in the UK are already recording suspected and convicted rapists as female if they choose to identify as such.
“Even if you think no trans-identifying male would ever be a threat to women, there is the issue of consent,” said McAlpine in an interview with a Sunday newspaper. “Why should a woman be forced, for example, to have an intimate procedure from a person she sees to be male?”
The MSP is not alone in her objections to the SNP legislation, and an SNP Women’s Pledge group, launched during the party’s conference, had attracted nearly 3,000 signatures by the weekend.
Arguing that women must maintain the sex-based protections granted to them in the Equality Act of 2010, the pledge reflects the deep divisions over the matter among Nationalists.
But, of course, it is not a dilemma for them alone. McAlpine’s predicament – she has been subjected to abuse online and by colleagues – is mirrored elsewhere. Some women have been physically attacked for speaking out, the MSP said.
A bigger worry, she added, was that medical professionals are seeing young people making irreversible changes to their bodies because they are encouraged to think they are the “wrong” sex.
In the climate of censorship that prevails, people are allowed to select their gender but not their point of view.
Feminist icons such as Germaine Greer are denied platforms at universities because they are advocates of women’s rights. Controversial Greer may be, but who would want to live in a world where she is banned from being controversial? And what about her rights, an octogenarian who earns her living from public discourse?
In picking fights with anyone who challenges their sometimes extreme positions, trans activists and the governments who indulge them are entering the dangerous territory of totalitarianism.
There is much to discuss. For example, should a transgender cyclist, with the competitive advantage of testosterone, be allowed to compete in a women’s race? At the very least, the subject, however uncomfortable, must be aired and public opinion consulted.
We don’t live in a society that prohibits free speech and is doctrinaire on social mores – not yet, anyway. But if we silence the likes of McAlpine and Greer, we turn back the clock to an age of greater repression. No one, whatever their gender, should wish for that.