Parents with infants use a variety of popular sources to get information about children’s milestones and play. The quality of these popular sources is unclear, and it may be difficult for parents to discern which information is accurate and how to find reliable sources. Our goal was to systematically review the resources accessed by parents.  By collecting information on these sources, we may be able to identify more accurate and unbiased sources on milestones and play for young children to which parents should be directed.