TEMPE, Ariz.-Relentless.

Marcus LeDeaux, 14, walks with a slight limp. A helmet sits askew on his head, concealing a bandage on his forehead but not the wound next to his ear. His lively eyes look everywhere but at you. He wears gloves that expose his finger tips. His mouth is curved into a smile that suggests a secret.

Despite his limp, Marcus is quick. In three minutes he does the following: Sits on his mother's lap. Paws through a bin of plastic sea creatures. Picks up an orca. Puts it in his mouth. Sniffs. Bites off a hunk of fin. Sniffs. Grabs a pair of scissors. Sits on his mother's lap. Taps at a computer keyboard. Explores a take-out box of food. Eats something. Roots through a drawer. Rifles through the bin of plastic toys. Pulls a book off the counter. Sniffs it.

Marcus is autistic. He also has a mild case of cerebral palsy.

I met Lisa, his mom, at Love Child, a children's resale shop she bought several years ago, after working there for more than a decade. Located next to the Trader Joe's in Tempe, the store brims with baby equipment, racks of gently used clothes, and shelves loaded with toys and books. In a moment of quiet before Marcus and his dad, Mark, arrive, Lisa sorts and prices clothes while describing how she learned that Marcus had autism.

They received the cerebral palsy diagnosis for Marcus, their third child, when he was 6 months old. When Lisa and Mark took him for evaluation to see if he'd qualify for government-paid services, the psychologist (and later a neurologist) diagnosed his autism. He was only a year old-much younger than most children who receive that diagnosis. After a few months of bureaucratic delay, Marcus began to receive crucial early intervention. The CP diagnosis has made it easier for Marcus to get services. He has long-term care, which has paid for five surgeries. It pays for his helmets.

Marcus also receives therapy, but after seven years of speech therapy still doesn't talk. He gestures, grunts, and squeals to get what he wants. He understands what people around him are saying, but doesn't appear to be paying attention. When he's happy, sad, or overstimulated, he'll head butt or pinch.

Sometimes he bites his fingers or hits himself repeatedly on the head-hence the gloves and helmet. He takes his helmet off, revealing short brown hair and a bandage covering a self-inflicted wound, before quickly pulling it back on. It gives him a feeling of security, his mother says. Although some people with autism shut themselves off from sensory experiences, Marcus drinks them in. "He's trapped in sensory land," his mother explains. "He has to smell everything."

I don't really understand what that means until I watch Marcus in action. He's constantly in motion. At one point he draws near to me as though he's going to kiss my cheek, but he moves past without making contact, sniffing me in passing. Even when he appears to snuggle with his mother, he's not really connecting. He's touching, feeling, and smelling to satisfy his appetite for sensory experiences. Lisa waves a finger three inches from his nose and mouth, causing explosive laughter. His brother calls it a wireless tickle.

For his first seven years, Marcus was so hyper he couldn't sleep. "He was wound for sound," his mother says. His parents, along with his grandmother, took shifts to get through the night. When he was seven, they accidentally discovered a cure for his sleeplessness. Lisa put her older son's ADD medication on the kitchen counter. Thinking it was candy, Marcus grabbed it and put it in his mouth before his brother, who was standing right there, could pick it up. He fell asleep. Now he takes medication and sleeps better.

The incident with the medicine turned out well, but it highlights what can happen when Marcus is unattended even for a second: "He ate the guts [foam rubber] out of the couch. ... He would try to eat bird poop. He would try to eat dead snails. ... He dug in his diaper and smeared feces everywhere." He doesn't do those things as much anymore, but recently he did open a drawer at Love Child and drink from a bottle of aloe vera lotion.

Relentless.

Few people have it as hard as Marcus, and few people display such joy. It's one of many paradoxes. Lisa calls him her greatest blessing and her greatest curse. Life with him is exhausting. She can't take him to church or on vacation. The isolation can be intense. "And the despair, so much despair. If you are ever alone and quiet, you cry and cry. ... There isn't anything anyone can do."

Exhaustion, despair, disagreements over treatment, and financial pressures-"We're a daily thread hanging on"-brought the LeDeaux family to a crisis point two years ago. Mark handled the pressure by drinking. He lost his job, and he and Lisa separated-after 22 years of marriage. During that period of separation, Mark and Marcus moved to an apartment, and Lisa lived with Marcus' older sister and brother. Mark almost gave up. Mark and Lisa considered turning Marcus over to the state of Arizona for care.

Autistic people fall on a spectrum, with Marcus toward one end and Temple Grandin, who earned a doctorate in animal sciences, at another. In between are people with varying degrees of disabilities affecting communication, the ability to develop social relationships, and behavior-and it is hard to know where any one child will fall.

One child somewhere in the middle is William Fowler. His parents knew something was wrong long before William received his official diagnosis at age 2. Melanie Fowler, a special education teacher and speech pathologist, worked with autistic children while pregnant with William. She recognized worrisome symptoms-his failure to make eye contact and hand flapping-but since the pediatrician wasn't concerned, Fowler hesitated. She worked on language skills with William at home and felt the stress and uncertainty building. Her first reaction: "What do I need to do to make this go away?" Then the realization: "It's not going to go away."

William's autism spectrum disorder (ASD) took its toll on the family. As the economy slowed in 2008, so did Seth Fowler's job selling new homes. Less income came in. After a frustrating day of work, he'd come home to find a child soiling the floor instead of his diaper, a wife who had dealt with a difficult child all day, and increasing financial demands created by the ASD.

Overwhelmed.

ASD is such an intense disorder that desperate parents are ripe for scam cures and expensive therapies, many of which are unproven. Melanie's professional background made her more able than many parents to sort through the options, but even she admitted the temptation to "sell your house to pay for therapy." With less money coming in, Seth often felt as though they were "chucking money out the window. This is hard-earned money and we are spending it on speculation."

An autism diagnosis is hard on marriage. Guilt eats at mothers, who wonder if they did something wrong during pregnancy. Day-to-day behavioral and communication problems add up. For dads especially, an ASD kills dreams of having a son who is a "chip off the old block." As Seth Fowler put it, "I couldn't relate to William at all. If I were to leave, he wouldn't miss me. You give and give and give and get nothing in response. ... It was brutal. I was angry, scared, confused."

As many as 80 percent of couples divorce, leaving many single moms alone to raise their ASD kids. Seth Fowler understands that statistic: "We were often at each other's throat ... only the grace of God kept us together." The Fowlers describe their experience in Look at My Eyes (Brown Books, 2011).

Eventually Seth found a group of male friends he could lean on. The Fowlers found people with whom they could leave William for a few hours to get a much-needed break. Over time, church members who might not be familiar with autism, and might find William's behaviors scary, were willing to learn how to care for him.

What does the future hold? William Fowler is nimble on the monkey bars and is learning to swim with his face in the water. He reads better than many children his age. He loves numbers. But his disability is apparent when his parents try to communicate with him. They often have to get on their knees and say, "Look at my eyes, William." It may take several repetitions, but when he does look up and make eye contact it is like a slow internet connection that suddenly connects.

Melanie Fowler says that William understands what they say, but he processes it differently. He can label thousands of pictures, but his outward speech is limited. He knows what he wants but he can't express it. That frustration sometimes boils over into tantrums. According to the Centers for Disease Control and Prevention, two out of five children with an ASD do not talk at all. Another quarter develop speech before the age of 2, but then lose it. Two out of five have an IQ less than 70.

William attends the nonprofit Jane Judson School, part of the Child Study Center in Fort Worth, Texas, where he receives year-round, all-day education. It is expensive-$10,000 a year for tuition and $10,000 for speech therapy-with neither insurance nor the government covering those costs. Seth Fowler says they chose it because "he's not one of the 'weird' kids in the class like he was in other classrooms."

Most children with an ASD attend public schools, receiving services under the Americans with Disabilities Act. Although younger children are eligible for services, many don't get diagnosed until they enter school. Even then the services they receive are highly dependent on their parents' socioeconomic status and ability to push through bureaucracy. A Los Angeles Times series documented how poor and minority children in California are much less likely to be diagnosed and receive services than kids from affluent families, even when the poor kids have greater disability.

In an age of budget restraints, parents are paying close attention to the American Psychiatric Association, which plans to announce next year changes to the definition of ASD. The new definition defines more narrowly the combination of symptoms that merits a diagnosis and will likely make some current recipients ineligible for services.

Will William continue to develop academically and go on to college? The Fowlers hope so, but they understand he might not. They keep their expectations high, wanting him to be an active member of society and not a burden. Part of William's success will depend on his connections to church and his sister Margaret.

She used to ask her parents why William was so upset or why he wouldn't talk to her. Now she knows that her brother has autism. Melanie Fowler deliberately creates experiences that bring William and Margaret together. Ultimately the Fowlers are impressing on their children the understanding that William was "not an accident. God was not surprised. William is a gift."

The turning point for the LeDeauxes, facing relentless personal and financial pressures, came when Lisa told Mark to leave. He went out, but came back and said, "You can't make me leave." That's when it turned around. The meetings they had been having with officials to discuss turning Marcus over to the state kept ending with Lisa in tears: "I just couldn't do it." The officials finally decided that the best and most cost effective plan was to give the LeDeauxes the respite care and support they needed to care for Marcus at home.

A couple of months have passed since the family reunited. Mark continues to be the primary caregiver for Marcus. Lisa continues to work at her shop. She says the separation was painful after 22 years of marriage, but God had to make each of them willing to change. Mark chose to give up drinking: They now have an alcohol-free home. Lisa had to stop being so critical about the way Mark handles Marcus, especially now that the boy is older. Since Mark is the primary caregiver, she had to let him do it his way, which means more discipline and structure. They've seen benefits from Mark's approach: Marcus now urinates in the toilet and doesn't need a diaper during the day.

Lisa still listens to sermons through oneplace.com, a central clearinghouse for preachers like R.C. Sproul and Adrian Rogers. Without a church community, she relies heavily on her parents: "If I didn't have family, I don't know what I'd do." Her friendships with the people who work and shop at Love Child help.

In the store for most of my visit, Mark has been quietly keeping his eye on Marcus. I ask about the reasons that so many fathers of autistic children leave. He said, "Conflicts with the mother about how care should be given" probably account for part of it.

What would he say to a father whose son just received an autism diagnosis? "The results are not going to be quick. You have to be patient." He goes on to explain how friends and family can offer encouragement: "Getting Marcus to use a potty is a huge accomplishment for us. It might not seem like much to other people. They have to reinforce the positive, celebrate the victories even if they don't seem big. You have to high five 'em. Hooray, hooray them."

Mark and Lisa LeDeaux know that Marcus will always be dependent on someone for care. That worries Mark: "Someday I'm not going to be able to deal with him. ... There's a lot of bad out there. People who might abuse him. He might run into someone without the patience to care for him."