If the subject is kids and how they’re raised, it seems our culture has exactly one story to tell: Parents today either can’t or won’t set limits for their children.

Instead of disciplining them, they hover and coddle and bend over backward to protect their self-esteem. The result is that we’re raising a generation of undisciplined narcissists who expect everything to go their way, and it won’t be pretty when their sense of entitlement crashes into the unforgiving real world.

Read 10 articles or books on this topic and you’ll wonder whether one person wrote all of them, so uniform is the rhetoric.

The central premise is that the problem’s dimensions are unprecedented: What’s happening now contrasts sharply with the days when parents weren’t afraid to hold kids to high standards or allow them to experience failure.

That’s why this generation is so self-centered. Take it from journalist Peter Wyden, the cover of whose book depicts a child lounging, eating grapes while Mom fans him and Dad shades him from the sun: It has become “tougher and tougher to say ‘no’ (to children) and make it stick,” he insists.

Or listen to the lament of a parent who blames child development experts for the fact that her kids now seem to believe that “they have priority over everything and everybody.”

Or consider a pointed polemic in the Atlantic. Sure, the author concedes, kids have always been pleasure-seekers, but longtime teachers report that what we’re now witnessing “is different from anything we have ever seen in the young before.” Forget about traditional values: Things come so easily to today’s entitled children that they fail to develop any self-discipline.

Powerful stuff. Except that those three indictments were published in 1962, 1944 and 1911, respectively.

The revelation that people were saying almost exactly the same things a century ago ought to make us stop talking and sit down — hard. So let’s consider three questions: Are parents unduly yielding or overprotective? Are kids today unusually narcissistic? And does the former cause the latter?

Everyone has an anecdote about a parent who hovered too close or tolerated too much. But is it representative of American parents in general? Does research tell us how pervasive permissiveness really is?

My efforts to track down national data — by combing both scholarly and popular databases as well as asking leading experts in the field — have yielded absolutely nothing. Scholars have no idea how many parents these days are permissive, or punitive, or responsive to their children’s needs without being permissive or punitive.

Thus, no one has a clue whether parenting has changed over the years. Researchers have shown that various practices are more likely to produce certain outcomes, but they shrug when asked how prevalent those practices are.

Similarly, “you will find next to no scientific data on ‘helicopter parenting,’ ” says Keene State College psychologist Neil Montgomery, using the popular term for parental overinvolvement.

We do know that corporal punishment remains extremely popular. In a 1995 Gallup poll, 94 percent of parents of preschoolers admitted to having struck their children within the previous year, a fact that’s not easy to square with claims that parents have become softer.

There’s also endless demand from parents for advice on getting kids to do what they’re told. Some of the recommended methods have shifted over the years, but the goal is still compliance.

A verbal reward such as “Good job!” is just the mirror image of punishment — a tool for eliciting obedience. The same is true of much “overparenting”: It’s an exercise in control. Yet both are often portrayed as signs of indulgence.

When the conversation turns to what the kids themselves are like, we find separate complaints sloppily lumped together: They’re rude, lacking in moral standards, materialistic, defiant, self-centered, excessively pleased with themselves and more.

What are interchangeable, in style and substance, are the polemics themselves — books with titles such as “Overindulged Children,” “Spoiling Childhood,” “The Myth of Self-Esteem,” “Generation Me,” “The Narcissism Epidemic,” and countless articles in the popular media. If you’ve read one of these, you’ve read them all.

Like the “permissive parents” trope, the notion that kids are full of themselves and out of control is decades, if not centuries, old — despite the critics’ assertion that things are worse than ever.

Jean Twenge, who wrote the last two books on that list, attacks anything that deviates from back-to-basics education and old-fashioned parenting. But unlike her peers, she has actually collected some data — which have received widespread and largely uncritical media attention.

Twenge, along with fellow psychologist Keith Campbell, has looked at surveys of young people conducted over several decades. They report that recent groups say they like themselves somewhat more, are more confident and score higher on questionnaires intended to measure narcissism than earlier groups.

Other researchers doubt these findings, raising multiple concerns about Twenge’s methodology. Kali Trzesniewski at the University of Western Ontario and Brent Roberts at the University of Illinois conducted their own analyses, with additional data, and discovered no meaningful differences across generations.

Why are we so willing to believe that kids today are excessively self-centered? Social psychologists say we selectively notice and remember examples that confirm our assumptions: My cousin knows a 20-year-old who refuses to work hard. I knew it was true!

But why would we gravitate to these beliefs in the first place? In a recent scholarly article, Roberts and others explained that complaints about a “Generation Me” — Twenge’s snide label — reflect people’s age, not the age they live in.

“When older people are told that younger people are getting increasingly narcissistic, they may be prone to agree because they confuse the claim for generational change with the fact that younger people are simply more narcissistic than they are,” Roberts and his colleagues write. “The confusion leads to an increased likelihood that older individuals will agree with the Generation Me argument despite its lack of empirical support.”

In short, they argue, “every generation is Generation Me” — until it grows up.

There’s no evidence, then, that today’s parents are more permissive than parents of yesteryear, or that today’s young people are more narcissistic. But even if there were, no one has come close to showing that one causes the other.

In fact, a pair of recent studies cast serious doubt on that proposition. The first, published in Pediatrics last May, discovered that there is indeed a parental practice associated with children who later become demanding and easily frustrated. But it’s not indulgent parenting. It’s spanking.

And in a small unpublished study of the effects of helicopter parenting on college students, Keene State’s Montgomery did not discover any sense of entitlement or tendency to take advantage of people among students who were closely monitored by their parents; to the contrary, such students tended to be somewhat anxious — and also had positive qualities, such as “the capacity to love, feel supported and seek out social connections.”

Neither logic nor evidence seems to support the widely accepted charge that we’re too easy on our children. Yet that assumption continues to find favor across the political spectrum. It seems that we’ve finally found something to bring the left and the right together: an unsubstantiated knock on parents, an unflattering view of kids and a dubious belief that the two are connected.In short, they argue, “every generation is Generation Me” — until it grows up.