“Ageism is the last acceptable prejudice in America—that and Asian drivers.” That’s not my line, though I wish it were. It’s Bill Maher’s, in a rant about how Jerry Brown is the best governor in the U.S. but isn’t considered a viable presidential candidate. Why? Because he’s 77. “Only in America is age more important than the fact that Jerry Brown took a broken state and fixed it. And he did it in his 70s,” Maher said. “Call Ripley’s—he must have taken governing Viagra.”

As Maher points out, discriminating on the basis of age is stupid because age is relative. (“Diana Nyad was 64 when she swam from Cuba to Florida. Lindsay Lohan is 28 and can’t make it across the room.”) And like all prejudices, age discrimination is punitive. It affects everyone, from high school kids who get Botox (“teen toxing!”) to the fastest-growing population group—people over 85—who face infantilization, segregation and abuse in their daily lives. But thanks to celebrities such as Maher and Madonna, 2016 may mark the year ageism finally lands on our cultural radar.

“I feel like it’s a form of discrimination that still hasn’t been dealt with,” the Queen of Pop told Access Hollywood earlier this year. “I think it should be as verboten as making racist or homophobic remarks.” And she’s right. “I can’t wait to grow old,” Lena Dunham tweeted, “and I can speak to how youth is fetishized/commodified until your age is your sexiest detail. I’m so over it.” When 37-year-old Maggie Gyllenhaal recently revealed she was told she was “too old” to play a 55-year-old’s lover, the news went viral, a sign of ageism’s growing ability to raise hackles.

It’s not that aging sets people off-limits, especially celebrities. (Another Maher quip: “Jerry Brown’s so old his sex tapes are on Betamax.”) It’s not that sexism and racism are behind us, even a little. It’s that humor is acceptable, while discrimination is not. The discomfort that makes these jokes funny is not evenly distributed. Sexist and racist remarks no longer get a pass in our society, but older people are seen as fair game. Who even blinks when old people are described as confused or repulsive?

Why should we care? Self-interest, for starters. Ageism is discrimination against a group to which we all aspire to belong. But bias is often unconscious, and rationality has little to do with it. Age doesn’t make people ugly or wise or boring; bias does. When it comes to age, stereotypes are inherently false, because the longer we live the more different from one another we become. When stereotypes go unchallenged, they become part of our identity—internalized ageism. A form of self-loathing, it damages our sense of our selves, filling us with needless dread. It’s needless because most of our assumptions about aging are off base. Late life is infinitely more pleasurable than we imagine. Older people shop for things besides prescription drugs! They have sex! The overwhelming majority of older people lead independent lives, and the older they are, the less they fear dying. Study after study shows people to be happiest at the beginning and end of their lives (see “Grading on a Curve,” below).

People who know this behave differently from those convinced that growing old means becoming pitiable or invisible. They take better care of themselves, do better on memory tests, walk faster and are more likely to recover from severe disability. And they live longer—an average of seven and a half years longer. Think what overturning ageist stereotypes would do to extend not just our life span but our “health span.”

We’re all worried about some aspect of growing old, whether running out of money, getting sick or ending up alone. Those fears are legitimate and real. But it never dawns on most of us that old age—or middle age or even just aging past youth—can be better or worse depending on the culture in which it takes place. And ours is grotesquely youth-centric.

Change begins when we acknowledge and let go of the prejudices that have been drummed into us since childhood by popular culture. Wrinkles are ugly. Old people are incompetent. It’s sad to be old. Absorbing them is effortless; banishing them is harder. Unlearning is difficult, especially when it comes to values, but we must watch for ways in which we’re ageist instead of merely looking for evidence that we’re not.

Wonder whether something you see or hear is ageist? See if a similar comment on the basis of race or sex would trigger an alarm. Take the reasoning that always crops up around health care rationing, for example: Why should we spend money on older people instead of on kids? Now imagine saying that we can afford to care for only straight people or only white people. Why should allocating resources by age be any more acceptable? How about our definition of diversity? We know it means including people of different races, genders, abilities and sexual orientations—why isn’t age a criterion?

Don’t let comments that wouldn’t fly on the basis of race or sex pass just because they’re about age. When we speak up about such inequalities, change ripples outward. If marriage equality is here to stay, why not age equality? If gay pride has gone mainstream and millions of Americans now proudly identify as disabled, why not age pride? The only reason that phrase sounds outlandish is because this is the first time many have encountered it. It won’t be the last.

Aging is difficult, but the passage of time confers very real benefits. Older people exhibit better judgment, become more emotionally adept and often grow more creative. No one reaches 80 without encountering adversity and loss, but life remains very much worth living. By blinding us to those benefits and heightening our fears, ageism makes growing older in America harder than it has to be. Most of w hat we know about aging is wrong—and staying in the dark serves commercial and political interests that don’t serve ours.

In the 20th century the civil rights and women’s movements woke us up to entrenched systems of racism and sexism around us. More recently, the gay rights movement has made great strides against homophobia. It’s high time to mobilize against age-based discrimination and stereotyping. Otherwise, ageism will pit us against one another. It will rob society of a vast amount of knowledge and experience. And it will poison our futures by framing longer, healthier lives as problems instead of the remarkable achievements they represent.