Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Developmental milestones are tasks most children learn, or physical developments, that commonly appear in certain age ranges. For example:
- Ability to lift and control the orientation of the head (Neck control) is attained at about 3 months
- Crawling begins at about 7 months
- Walking unsupported is attained at about 12 months
- Speech begins
- Voice lowers in pitch (especially noticeable in boys)
- Pubic hair appears
- Genitals and reproductive organs mature
- Menses begin (females)
- Body hair and facial hair appears
"Normal" age ranges for many milestones are broad (a factor of 1.5 - 2 from bottom to top is possible). For this and other reasons, a single delayed milestone, especially task-related, is rarely in itself a basis for diagnosing a problem.
Note: the Tanner stages can be used to approximately judge a child's age based on physical development.
- CDC's "Learn the Signs. Act Early.” campaign - Information for parents on early childhood development and developmental disabilities
- March of Dimes
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