While details are hotly debated, nearly all experts agree: The key is to start early.
"The earlier you start a child in this treatment, and the more intense the treatment, the better they do," says Dr. Michael Morrier, assistant director of the Emory Autism Center at the Emory University School of Medicine.
In one landmark study, among children who began treatment before turning 3, nearly half improved to the point where they were indistinguishable from same-age peers.
The treatment is intensive, often requiring 30 or 40 hours a week in a one-on-one or small group setting. Providers are in high demand and sometimes have to drive hundreds of miles to see children, further adding to the cost.
Melissa Solares says that she and her husband, a surgeon in Augusta, Georgia, spent $115,000 on treatment the year after their son Arturo was first diagnosed.
A "shadow" accompanies Arturo to school each day, and for up to four hours a day after school another aide helps Solares conduct the formal one-on-one coaching that's the hallmark of behavioral therapy. Twice a week, a more experienced therapist visits from South Carolina to make sure the therapy is being done correctly.
It seems to work: When Arturo was diagnosed at age 4, he still wasn't toilet-trained and could speak less than 50 words, Solares recalls. Barely 15 months later, he's speaking in full sentences and attends a regular, private preschool. "He's a completely different child," Solares says.
Her family is stretched thin. If the Georgia bill doesn't become law, she and her husband will be looking to leave the state for one that requires insurance companies to cover Arturo's treatment.
Despite the financial strain, she feels fortunate. "We have resources, but what do people do who have to work all day, if they can't do therapy themselves?" she asks. "Those children just get thrown in a corner and wasted."
Bullard's parents had a college fund set aside that they let the family use for Ava's treatment. Her church and friends in their Vidalia, Georgia, community also pitched in. "We used all the savings we had, and then some credit cards," Bullard says. "We just did whatever."
There were compromises. For example, Ava got one home visit a month instead of the recommended two or three, and each session with the therapist was shorter.
Even so, it paid off. Within two weeks of her first therapy session, Ava was sitting at the dinner table, something she'd never been able to do. Today, she no longer needs intensive treatment -- just one session a week to practice social skills.
Bullard says a mandate would give other children a chance at the same success Ava's had. "She's in third grade, completely indistinguishable from her peers, because treatment works," says Bullard.
Until getting word of the hearing, the three mothers were feeling glum. Even friendly legislators weren't returning calls. At one point, Solares literally ran down a hallway, baby in arms, chasing a senator who had previously pledged support. He didn't look back.
The promise of a hearing offers a ray of hope. It might be too late to get a vote on Ava's Law this spring, but Albers is looking for another bill where the autism mandate might be attached as an amendment. "Anything's possible," he says.
Back at the Senate chamber, Ava is smiling but tired after getting word of the hearing. Near her breaking point, she turns to her mom and says simply, "I'm ready to go home."