When Lisa Quinones-Fontanez’s son Norrin was diagnosed with autism at age 2, she and her husband did what most parents in their position do — they scrambled to form a plan to help their child.

Ultimately, they followed the experts’ advice. They put Norrin in a school that used applied behavioral analysis, or ABA, the longest-standing and best-established form of therapy for children with autism. They also hired an ABA therapist to direct a home program.

ABA involves as much as 40 hours a week of one-on-one therapy. Certified therapists deliver or oversee the regimen, organized around the child’s individual needs — developing social skills, for instance, and learning to write a name or use the bathroom. The approach breaks desirable behaviors down into steps and rewards the child for completing each step along the way.

ABA was tough on everyone at first, says Quinones-Fontanez: “He would cry sitting at the table during those sessions, hysterically cry. I would have to walk out of the room and turn on the faucet to tune it out because I couldn’t hear him cry.”

But once her son got settled into the routine of it, things improved, she says. Before he began therapy, Norrin did not speak. But within a few weeks, the ABA therapist had Norrin pointing his fingers at letters. Eventually, he learned to write letters, his name and other words on a dry-erase board. He could communicate.

Norrin, now 10, has been receiving 15 hours a week of ABA therapy at home ever since. He is still in an ABA-based school. His therapists help him to practice age-appropriate conversation and social skills, and to memorize his address and his parents’ names and phone numbers.

“I credit ABA with helping him in a way that I could not,” Quinones-Fontanez says. “Especially in those first few years, I don’t even know where we would have been without ABA therapy.”

But in recent years, Quinones-Fontanez and parents like her have had cause to question ABA therapy, largely because of a fiercely articulate and vocal community of adults with autism. These advocates, many of them childhood recipients of ABA, say that the therapy is harmful. They contend that ABA is based on a cruel premise — of trying to make people with autism ‘normal,’ a goal articulated in the 1960s by psychologist Ole Ivar Lovaas, who developed ABA for autism. What they advocate for, instead, is acceptance of neurodiversity — the idea that people with autism or, say, attention deficit hyperactivity disorder or Tourette syndrome, should be respected as naturally different rather than abnormal and needing to be fixed.

“ABA has a predatory approach to parents,” says Ari Ne’eman, president of the Autistic Self Advocacy Network and a prominent leader in the neurodiversity movement. The message is that “if you don’t work with an ABA provider, your child has no hope.”

What’s more, the therapy has a corner on the market, says Ne’eman. Most states cover autism therapy, including, often, ABA — perhaps because of its long history. But in California, for example, parents who want to pursue something else must fund it themselves.

These criticisms haven’t made Quinones-Fontanez want to ditch Norrin’s ABA therapy, but they confuse her. She says she can see what the advocates are saying on some level; she does not want her son to become a ‘robot,’ merely repeating socially acceptable phrases on command because they make him seem like everyone else. Sometimes Norrin will approach friendly people on the street and say, “Hello, what’s your name?” as he’s been taught, but not wait around for the answer, because he really doesn’t understand why he’s saying it. “He just knows to do his part,” she says.

The message that ABA might be damaging distresses her. “I’m trying to do the best I can. I would never do anything to hurt my child,” she says. “This is what works for him; I’ve seen it work.”

Whether ABA is helpful or harmful has become a highly contentious topic — such a flashpoint that few people who aren’t already advocates are willing to speak about it publicly. Many who were asked to be interviewed for this article declined, saying they anticipate negative feedback no matter which side they are on. One woman who blogs with her daughter who has autism says she had to shut down comments on a post that was critical of their experience with an intensive ABA program because the volume of comments — many from ABA therapists defending the therapy — was so high. Shannon Des Roches Rosa, co-founder of the influential advocacy group Thinking Person’s Guide to Autism, says that when she posts about ABA on the group’s Facebook page, she must set aside days to moderate comments.

Strong opinions on both sides of the issue abound. Meanwhile, parents like Quinones-Fontanez are caught in the middle. There’s no doubt that everyone wants what is right for these children. But what is that?