Jacob and Tyler, 24-month-old twins, seem to be following different developmental paths. Jacob said simple things like “uh-oh” when he was 1 year old. Now he puts two words together to ask for what he wants. Jacob says things like “eat cookie” and he points to the cookie. The boy loves to be with other children and loves to play make-believe. Sometimes he pretends to call his grandma on the phone.

Then there’s Tyler. The same age as Jacob, Tyler doesn’t use words to say what he wants. He plays with only one toy— his “favorite” toy— and sings one song over and over again. Tyler is able to say words. But it seems to his mom that Tyler repeats what she says to him instead of truly responding. He doesn’t make eye contact with his mom and doesn’t appear interested in playing with other children.

Is Jacob advanced for his age or is Tyler delayed?

Developmental Milestones

As they grow, children are always learning new things. Skills such as taking first steps, smiling for the first time and waving “bye-bye” are called developmental milestones. You can follow your children’s development by watching for these milestones and others while children play, learn, speak, move and act. Watching for these milestones can help you determine if your child is on track for his or her age or if he or she might have a developmental delay.

Some Milestones to Look for in the First Three Years

By 9 months

  • Plays peek-a-boo
  • Strings different sounds together, such as mama and dada, when babbling

By 1 Year (12 months)

  • Responds to simple spoken requests
  • Uses simple gestures, like shaking head “no” or waving “bye-bye”

By 18 months

  • Says and shakes head “no”
  • Finds a hidden object even after it’s been moved once or twice

By 2 Years (24 months)

  • Copies others, especially adults and older children
  • Uses sentences with two to four words, such as “drink milk”

By 3 Years (36 months)

  • Plays well with two or three children in a group
  • Recognizes and names almost all common objects and pictures

You can print milestone checklists for children ages 3 months to 5 years at www.cdc.gov/actearly/.

As you watch your child develop, trust your instincts and look for milestones to gauge whether your child’s development is on track. Keep in mind however, because every child develops at his or her own pace, it’s important to remember that a child may reach these milestones slightly before or after other children the same age.

Developmental Screening

Doctors and nurses use developmental screening to tell if children acquire basic skills when they should. All children should be screened to assess their general development at 9, 12, 18 and 30 months old. In addition, the American Academy of Pediatrics recommends that all children be screened for autism spectrum disorders (ASDs) at 18 and 24 months. As there is no lab or blood test to tell if a child may have an ASD, developmental screening helps indicate if the child needs to see a specialist.

Specialists who may be involved in screening and diagnosis include medical doctors (pediatricians, developmental-behavioral pediatricians, child psychiatrists, neurologists and clinical geneticists), psychologists, therapists (speech-language pathologists as well as occupational and physical therapists), special educators and audiologists.

Of course, the family and the child are at the center of this team of specialists. Family members should be instrumental in guiding the child’s diagnosis and intervention plan.

How Screening Helped One Family

Tyler and Jacob’s mom decided to talk with her children’s doctor at their annual checkup. She was worried about Tyler. She had monitored her children’s developmental milestones and learned that Jacob was on track for his age and Tyler wasn’t. At the doctor visit, she completed a general developmental screening questionnaire for both boys, followed by an autism-specific screening questionnaire for Tyler. The screening confirmed what she and the doctor had observed: Tyler was autistic. The family was referred to a specialist for further evaluation and given information about community-based resources and early intervention services.

Acting Early

Parents often ask what they can do to support and guide their child’s development. The foundation of ensuring healthy development is to make sure that your child gets good nutrition, exercise and rest. Providing a safe, nurturing and loving atmosphere, spending time with your child playing, singing, reading and talking as well as monitoring development make a big difference.

If you suspect that your child is not meeting his or her developmental milestones, if you notice a particular delay in one or more areas of development, or if your child loses skills he or she once had, seek advice. Don’t wait and see if your child “grows out of it.” The earlier a delay is recognized, the earlier you can get the help your child needs.

For more information, including a free Parent Resource Kit, visit www.cdc.gov/actearly. Stay updated on child development by following twitter.com/CDCActearly.