aving their hand, or shaking their head, then you should take them to their pediatrician.
Children develop at their own rate; they may just completely skip over a milestone or it may take a longer time for them to emerge. A missed milestone or two isn’t always a cause for concern, but it doesn’t hurt to pay a pediatrician a visit to consult with them about your child’s development or ask for a developmental screening. This test will reveal if there are any serious problems that need to be addressed.