The CDC says you know your child best. If your child is not meeting one or more milestones, has lost skills he or she once had, or you have other concerns, act early: talk with your child's doctor and ask about a developmental screening.
Related milestones
Frequently asked questions
When do babies start teething?
Baby teeth start to come in at about 6 months, according to the American Dental Association, and Seattle Children's Hospital says they come in between 6 and 24 months. There are 20 primary (baby) teeth.
When should I talk to a doctor?
The CDC says to act early if your baby is not meeting one or more milestones, has lost skills they once had, or you have other concerns. Talk with your child's doctor; you know your baby best.
Sources: CDC, "Learn the Signs. Act Early." milestone checklists; American Dental Association (MouthHealthy), "Eruption Charts"; Seattle Children's Hospital, "Teething" (reviewed May 1, 2025). Checked October 17, 2026. Not medical advice. Our sources.