When I first heard that autistic people didn’t have empathy, I assumed my son Mickey must be an exception.

He was not yet 2 when the developmental specialist told us all the things our child would never do. Pretend play. Eye contact. Empathy. I remember sitting on the floor of his bedroom days later, hugging my knees to my chest and watching Mickey build block towers, thinking, who was this child? Had he suddenly become a stranger?

At the sound of my sobbing, Mickey looked up. He put down the block in his hand. Stood. Toddled toward me. Bent down to peer searchingly at my face. Then he spread his arms wide and wrapped himself tight around me in a full hug. At that moment I realized he was exactly the same child I’d had before the diagnosis — an affectionate, playful little boy who was not yet speaking but already knew how to offer sympathy.

So why does this myth that autistic people lack empathy persist?

The reasons are complicated — a convergence of media, popular culture, and ignorance. But if you want to lay blame, you might start with the British cognitive psychologists Simon Baron-Cohen and Uta Frith, who in the 1980s coined the much-loathed term “mind-blindness” for what they considered the core deficit in autism: the autistic person’s inability to employ a “theory of mind.” Meaning, essentially, that autistic people are incapable of imagining anyone else’s thoughts and feelings.

But empathy is a complicated construct. There is cognitive empathy, the ability to read other people’s feelings, but there is also affective empathy, the ability to share other people’s feelings. Just because you don’t have the social/cognitive skill to read someone else’s feelings doesn’t mean you can’t feel someone else’s pain. While it’s true that autistic people often have a harder time reading social cues, it is quite a leap — and a dangerous one — to assume that a person’s inability to interpret nonverbal cues means he doesn’t care and has no empathy.

Empathy is the trait that makes us human. So to say that autistics lack empathy is saying that they are less than human. And once you dehumanize others it becomes “permissible” to do things to them. To taunt and bully and abuse. Consider places like the Judge Rotenberg Center in Massachusetts, a so-called treatment center for people with autism that uses painful electrical shocks to the skin to punish self-injurious behavior. That’s not treatment. That’s torture.

And if you still don’t think this kind of thinking is dangerous, consider this.

In the wake of the Sandy Hook school massacre, as some people speculated that the shooter Adam Lanza might have been on the autism spectrum, hate groups began showing up on Facebook. One group calling itself “Asperger’s Prevention Campaign” posted this: “When we reach 50 likes, we will find an autistic kid and set it on fire.” (Facebook has since removed the group.)

Everyone in the autism community knows the saying, “If you’ve met one person with autism, you’ve met one person with autism.” Some people on the spectrum may struggle with empathy; others can feel overwhelmed by other people’s feelings. Then there is everyone in between. You know what? That’s why we call it a spectrum.

Twenty years on, I have ample evidence that my son can read other people’s moods and react appropriately. He’ll frequently ask us such questions as “Are you tired?” “Are you feeling frustrated?” “Can I give you a hug to cheer you up?”

As journalist Steve Silberman, author of the forthcoming book NeuroTribes: Thinking Smarter About People Who Think Differently, says, “Calling autistics mind-blind may turn out to be as apt as calling those who don’t speak English deaf.”