When Julie Hibbert's twins were about 14 months old, the senior HR analyst from Huntington, NY, noticed that her son's fine motor skills were much less developed than his sister's and that he was prone to chronic repetitive behaviors like spinning a toy or stroller wheel around and around rather than actually playing. "If he didn't have a twin to compare him to, I might not have noticed or done anything so early," says Julie. She had her son assessed and soon learned that he had some developmental delays. Six months later he was diagnosed with an autism spectrum disorder.

The first smile. The first steps. The first word. These exciting moments reassure us that our children are thriving amidst the busy flurry of our home and work lives. But some children don't reach these developmental milestones when they should. According to the Centers for Disease Control and Prevention, 17 percent of U.S. children have some form of developmental disability, from mild speech and learning delays to more serious mental retardation and autism.

When it comes to identifying these challenges, we may not have the clear indicators Julie had. That's why it's critical that we trust our inner voice when something doesn't seem quite right—and then act on it. Identifying problems as soon as possible can improve children's prospects and quality of life.

"Catching it early is the most important thing you can do," says Linda Rubinowitz, PhD, a clinical psychologist at the Family Institute at Northwestern University in Evanston, IL. Even children who are eventually diagnosed with conditions such as autism, once thought to be virtually untreatable, can make measurable progress with effective intervention—particularly if treatment can begin early. "If you delay action when you know something is really off track, it doesn't get better," Dr. Rubinowitz says. "In fact, the gap gets larger between that child and his peers as they grow. If you get involved in the therapy early, you can really make some important gains. So don't wait."

Symptoms of developmental delays are varied and sometimes subtle. First Signs, a nonprofit that educates about developmental disorders, offers parents this timeline of "red flags":

  • No big smiles or other warm, joyful expressions by 6 months or older.
  • No sharing of sounds, smiles or other facial expressions by 9 months or older.
  • No babbling by 12 months.
  • No back-and-forth gestures, such as pointing, showing, reaching or waving, by 12 months.
  • No words by 16 months.
  • No meaningful two-word phrases (without imitating or repeating) by 24 months.
  • Any loss of speech or babbling or social skills at any age.

If any of these conditions is present, have your child screened to ensure he's on the right developmental path. Be bold in expressing concerns to your pediatrician. "Every time you go, raise what's happening developmentally with your child," says Dr. Rubinowitz. "Some pediatricians will not be responsive unless pressed a bit. So you need to trust your gut." Other assessment avenues: a developmental pediatrician, a child development clinic at a major hospital or university, or your local school system. And try not to let fear or stigma get in the way of addressing your child's issues. "It can be hard to accept that he's not going to meet some of the dreams you had for him," she adds. "It's a grieving process you need to get through. Then you need to dream new dreams."

Parents can help promote a healthy developmental pathway for a child with delays as they would for any child: by being loving, active and involved caregivers, by getting their support team (spouse, caregiver, day-care provider, grandparents) on board and by working creatively with a child's unique challenges and opportunities. "Parents who do can position their child to have a better chance to thrive later on," assures Dr. Rubinowitz.

Here are three types of developmental disorders affecting children today, plus how to spot them early on—and why.

Autism

This complex disability impacts social interaction and communication skills. Parents usually first notice a lack of these skills or delays from ages 15 to 18 months through 3 years. Children with autism spectrum disorders may be nonverbal and asocial, as with "classic" autism. On the other end of the spectrum are high-functioning forms of autism, such as Asperger syndrome, characterized by idiosyncratic social skills and play.

What to look for: In general, kids with autism are resistant to change, use gestures or pointing instead of words, laugh or cry for no apparent reason, prefer to be alone and resist cuddling or being cuddled. Often they'll make little or no eye contact, be over- or undersensitive to pain, have no real fear of danger and be unresponsive to verbal cues.

Why catch it early? Studies have found that children with autism have the best outcome if they are identified early and offered intensive and appropriate intervention, such as the occupational, speech and applied behavioral analysis therapies that Julie's son has received.

AD/HD

Attention-deficit hyperactivity disorder, AD/HD, is one of the most common neurobehavioral disorders, characterized by problems with inattentiveness, overactivity and/or impulsivity.

What to look for: Children as young as 2 often fidget with their hands or feet, can't sit still, are easily distracted and have trouble waiting their turn and following instructions. They may struggle to stay focused on tasks or play activities, talk excessively and interrupt others.

Why catch it early? When therapies like medication and behavioral training are put into action, a child has a much better chance of starting school on the right foot. Early diagnosis also may make a child eligible for educational accommodations like more time for tests and even a paraprofessional to work with the student one on one.

Learning Disabilities (LD)

This is a group of neurological disorders characterized by difficulty learning, sorting and storing information. They may not be spotted before school age.

What to look for: Children with LD may have one or more difficulties with skills like listening, speaking, reading, writing, reasoning or doing math that interfere with academic performance and sometimes daily life. LD may overlap with other disorders, such as AD/HD.

Why catch it early? When learning disorders are diagnosed early on, children may be eligible for LD classes that offer specific and intensive teaching, such as information presented in multiple formats and broken down into manageable chunks. Like so many developmental disorders, LD may be lifelong. But with proper and early intervention, training and strategies, affected individuals can lead satisfying, fully functioning lives.