Autism spectrum disorder (ASD) can be frightening to parents, in part because so much about the condition is still not well understood. Doctors and scientists are still trying to sort out the causes of autism, which expresses itself as a distinctive set of characteristics in children and adults, including difficulty with social interactions, trouble with verbal and nonverbal communication, repetitive behaviors, and narrow, obsessive interests.

How common is autism?

Statistics show that autism is on the rise: According to the Centers for Disease Control and Prevention (CDC), about 1 in 59 children are diagnosed with autism before the age of 8 — a number that has increased in every update since 2000, when just 1 in 150 children were diagnosed. It's also more than four times as common in boys as in girls, although that gap has narrowed over the years.

That said, statistics don't tell the whole story. Many experts say that increased autism rates may simply be due to more kids being diagnosed because of heightened awareness of the disorder, or because a wider range of developmental disorders are now being labeled as part of the autism spectrum.

What causes autism?

Despite what you may have heard, vaccines don't cause autism. In fact, the journal that published the original 1998 study linking the measles, mumps, and rubella (MMR) vaccine to autism retracted it, and the author was later found to have fudged his data and misrepresented the results (his license was revoked). Many subsequent large studies have also discredited the results.

Is too much TV to blame? Not likely, despite the fact that Cornell University researchers reported a link between increased television viewing by children under age 3 and rising rates of autism in a 2006 paper.

Some research suggests that other underlying factors may lead to autism, including genetic and chromosomal abnormalities, maternal rubella during pregnancy, or fetal brain damage late in pregnancy.

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Multiple studies over the past decade have also indicated that a parent's age might also have an effect on autism risk. One study found that women over 40 are twice as likely as those who are 25 or younger to have a child with autism, while other research has found that teens are 15 times more likely than 20-somethings to give birth to kids with autism. Another study found that children of fathers over the age of 45 have a 75 percent higher risk of developing autism than those born to dads in their early 20s.

Researchers additionally believe that a host of as-yet-unknown environmental factors might play a role in autism, including exposure to pesticides, chemicals in household products and viruses.

What early signs of autism should I watch for in my child?

While the causes of autism remain mysterious, the early signs of autism don't come out of nowhere. Most parents of autistic children recognize language delays at around 18 months of age. In fact, there are a few red flags that parents can look out for in their child much earlier than that. The American Academy of Pediatrics (AAP) says some subtle, early signs of autism to look for before baby is 12 to 18 months old include:

Your child doesn't turn when you say his or her name by 12 months

Your child doesn't turn to look when you point and say, "Look at…"

Your child doesn't point to show you interesting objects or events

Your child doesn't engage in back-and-forth baby babbling

Delay in smiling and laughing

Your child doesn't make and keep eye contact with people

Other early signs of autism that warrant evaluation by your pediatrician include the following (to name a few):

No babbling, pointing or other gestures by 12 months

No single words by 16 months

No two-word spontaneous phrases by 24 months

Loss of language or social skills at any age

What should I do if I think my child might have early signs of autism?

If your child has exhibited early signs of autism, talk to your pediatrician. He or she can use a standardized screening tool to determine if your child has autism or is at risk.

While there is no cure for autism, early intervention can make a big difference. Behavioral therapies can help kids develop social and language skills, for example, and medications can treat impulsive behavior and hyperactivity.

If you haven’t spotted any of these symptoms but are still worried your child has autism, try not to let your fears get in the way of enjoying your time with your son. Pay attention to his behavior patterns (and remember that even the healthiest children can be shy and remote at times), and ask questions of your pediatrician. Chances are he's just fine!

Here's to motherly love (and concern),