For her smear-test appointment at a London clinic, a woman had asked to be seen by a female practitioner. So you can imagine her surprise when she was approached for this intimate procedure by a bearded bloke with tattoos covering his arms. A deep voice said: ‘I don’t identify as a male; I’m a transsexual.’ So that’s all right, then. The woman complained to the NHS trust but felt that she was perceived as the problem. Meanwhile, female bathers who complain about male bodies being allowed in the Ladies’ Pond at Hampstead Heath are disparaged on social media as transphobic.

Two stories to get 2018 off to another adventure in cultural Marxism. But as I have suggested before, society is unlikely to bow to all the demands of transgender activism. Indeed, it could be a tipping point against the decadence of narcissistic identity politics that has threatened a repeat of the sacking of Rome, which was destroyed not so much by invaders but by the lassitude within.

An immediate problem for a reporter or common bystander is how to define the person who appears male but claims female gender: state what you see, and you could find yourself on the wrong side of the law. Organisations nervously toe the line, and millions of workers have received memos from politically correct, risk-averse bosses or personnel departments demanding that any person’s chosen identity be respected. Category error could cost you your job.

Until recently there was a clear distinction between sex and gender: the former your biological assignation and the latter a socially-constructed status. Sex is almost unexceptionally dichotomous: male or female. You are born with either XX (female) or XY (male) chromosomes. A small number of people who are genetically male grow up with female features owing to failed activation of the Y element. A man who dresses as a woman would be transgender, whereas a transsexual is undergoing or has completed a physical sex change, but this has been blurred by the current obsession with self-determination.

Society has been shaken by the sudden prominence of transgenderism, and questions are being asked about why there are now apparently so many people born in the wrong body. Was it because the battle for homosexual rights needed to be fought first, and that transgender people were actually as prevalent in the past, but forced to live a lie? To some extent this may be true, but I doubt if it satisfactorily explains the surge in boys and girls wanting to be girls and boys.

This is more a matter of nurture than nature. First, let us consider environmental influences. A study at Hebrew University of Jerusalem found that sperm count has declined sharply among men in North America, Europe and Australasia. Deterioration in quality and quantity of human seed has serious implications for fertility. Exposure to agricultural pesticides, food packaging and domestic cleaning agents may disrupt the balance of sex hormones. The contraceptive pill, by raising oestrogen levels in rivers, is blamed for a female excess in fish. Chemical castrators are pervasive: men are being feminised by the commodities of modern life.

Secondly, and perhaps partly as a result of chemical factors, our culture has embraced transgenderism to the extent of encouraging it. Good riddance to Justine Greening, whose progressive ministerial ambition was to overturn the sex dichotomy through radical legislation. But the momentum will continue, pushed by younger generations infused with the revolutionary subversion that attacks the family and traditional gender roles. The requirement for medical certification of sex change may not survive the Zeitgeist.

A Times editorial in November argued: ‘A confused debate about gender threatens to harm young people. Doctors and politicians need to summon the courage to tell them they are wrong.’ However, Myles Harris, general practitioner and editor of the Salisbury Review, fears that medical expertise has lost influence and can only shout from the touchline. ‘Alarm bells have begun to ring, far too late, with some GPs refusing to prescribe hormone treatments for children. Psychiatrists, surgeons and medical researchers have all begun to express serious doubts about the value of this type of surgery, pointing out the lack of evidence, and the possible serious long term effects, both psychological and physical, of changing one’s sex.’

Any doctor who challenges transgenderism risks censure. Paul McHugh, chief psychiatrist at Johns Hopkins Hospital in the USA, believed that people with gender dysphoria should be allowed to live as they are, with psychological help. He stopped sex-change operations at his hospital, although these resumed after his retirement in 2001. Six hundred LGBT activists wrote an open letter arguing that he ‘does not represent prevailing expert consensus opinion about sexual orientation or gender identity related research or clinical care’. Unperturbed by the Twitter storms, in a recent article McHugh described transgenderism as a ‘craze’.

McHugh’s reason for opposing sex reassignment surgery was his research data showing a high suicide rate. This, however, is anathema to the vociferous transgender lobby. James Caspian, a psychologist who is gay and a trustee of the transgender charity Beaumont Trust, also became aware of an increasing number of transgender men wishing that they had stayed female. His proposal to study people who regretted having a sex-change operation was blocked by the University of Bath ethics committee. While university administrators prioritise ‘values’ over empirical enquiry, Caspian noted that conversion one way is celebrated, but reversion is taboo.

For transgender campaigners, science is oppressive reductionism, a white heterosexual male construct. Biological and chemical causes are denied as ideology trumps scientific truth: transgenderism is a choice. Yet the sex change process is a medical intervention, deploying hormonal agents such as Cyproterone, and the careful building of a penis or vagina. I still think that transgenderism is a bridge too far, but as at Arnhem, the troops will find out the hard way. We mess with nature at our peril.