Can you think of anything more cruel than telling a five-year-old boy who likes Lady Gaga that he might have gender dysphoria? Or telling a nine-year-old tomboy who hates Barbie and loves Beckham that she might really be male - in spirit - and therefore she should think about putting off puberty and possibly transitioning to her 'correct gender'?

Saying such things to kids who are only doing what kids have done for generations - messing about, discovering their identity - turns playfulness into a pathology. It convinces boys who aren't boyish and girls who aren't girly that they must have some great gender problem, a profound inner turmoil that their tiny minds must address, when in truth they're just having fun. What an awful trick to play on children.

It's being played on them more and more. 'Transgender kids' - the quote marks are because I'm not convinced that toddlers are capable of thinking - are in the news. On Sunday, BBC 2 aired Louis Theroux's documentary on trans kids in America. Like all of Theroux's work, it was objective, observant and humane. It introduced us to Camille, a five-year-old, pink-loving, Gaga-admiring boy who daftly thinks he is a girl, and even more daftly is indulged by psychologists and his parents; Cole/Crystal, a boy who can't decide whether he is male or female (Cole, buddy, you're male) and whose confusion was heightened by the conflicting responses of the adults around him; and, saddest of all, Nikki, born Nick, a troubled 14-year-old boy who is taking drugs to put off puberty because, according to experts at least, he's transgender.

The trend for diagnosing gender dysphoria or transgenderism in kids who a couple of decades ago would simply have been seen as camp (boys) or unladylike (girls) is spreading. This week the BBC reported that the number of British kids under the age of 10 who are being referred to the NHS because they have 'transgender feelings' has quadrupled in six years. Forty-seven of these kids were aged 5 or under. Your four-year-old boy loves dancing in leggings to old Madonna songs? Quick, get him to the doctor! It's bizarre.

The NHS now prescribes puberty-blocking drugs to so-called trans kids when they turn 10 or 11. This seems especially cruel, to deny children that tough but essential transitionary period, that biological burst that turns girls into women and boys into gruff-voiced scallywags who might one day mature into men. We do not ask 10-year-olds to make major decisions in relation to their schooling, where they live, smoking or sex; and yet we now invite them to make the terrifying existential choice to offset adulthood itself, to keep their hormones locked in limbo, to determine what sex they are. What a terrible burden to put on a human being who probably isn't allowed to walk to the shop on his own or to stay up past 9pm.

We all now recognise that it was wrong and wicked to have castrato singers, males who were castrated before puberty in order to preserve their pure and feminine dulcet tones. The last-ever castrato died in 1922. Yet are we not doing something similar today, using drugs to keep boys (and girls) in a puberty-avoiding state, a childish limbo, having convinced them with psychobabble that they are dysphoric?

The treatment of non-conforming or plain funny kids as 'transgender' strikes me as a stunning abdication of adult responsibility. It is the job of adults to correct childish confusions, to guide kids through weird or rough patches, and ensure, to the best of our abilities, that they come out the other end as rounded, hopefully happy adults. But now, the cult of relativism runs so deep that adults even balk from making that most basic of all judgements - that a child with a penis is a boy and a child with a vagina is a girl - and instead we accommodate to the child's own fads and silliness.

What about children who want to be dogs, or dinosaurs, or racing car drivers? Should we indulge them? 'Transgender kids' aren't at fault at all here - the problem is an adult society that has so profoundly lost the plot that it can no longer steer and socialise the next generation, and can't even bring itself to say 'boys will be boys and girls will be girls' because to do so in our Queer Studies-saturated era is apparently to be discriminatory, judgemental, oppressive.

There's one more, seriously dark element to the promotion of the 'trans kids' phenomenon: it's being pushed by adult trans activists as a way of pursuing their own interests and agenda. More and more trans campaigners are using 'trans kids' effectively as a moral shield, hoping that if they can convince the world that transgenderism is something that emerges as early as three or four then it must be natural, good, healthy, and thus should be insulated from criticism.

That is, they're effectively experimenting on children, both socially and medically, both through filling kids' heads with nonsense about dysphoria and offering them drugs, in order to advance their own adult demands for greater recognition. This is repulsive, the creation of a new generation of castratos who are paraded and praised in public by self-serving trans activists who only want more political clout and respect. Stop it. Let kids be kids. A boy who plays with dolls is not trans or dysphoric - he's just a boy who plays with dolls.