Cribsheet: A Data-Driven Guide to Better, More Relaxed Parenting, from Birth to Preschool

The author discusses the significance of physical milestones in early childhood development, particularly focusing on walking. Oster shares a personal experience with her daughter Penelope, who started walking later than the average child. The narrative addresses the common parenting anxiety one may experience when their child does not meet expected milestones at the “normal” age, often leading to concerns and, in some cases, interventions like early childhood programs.

Oster emphasizes the wide distribution in typical developmental timelines, comparing it to the variability seen in children’s weight percentiles and reassuring parents that “it’s totally fine for your child to be at the 25th (or the 75th) percentile of weight” (210). The author acknowledges the importance of monitoring physical milestones, especially as delays may indicate underlying issues or conditions such as cerebral palsy or progressive neurological diseases.

Oster explains how pediatricians evaluate motor skills during well-child visits, looking for signs of developmental delays. She provides a list of milestones at 9, 18, and 30-36 months, emphasizing that significant delays may warrant attention. The chapter also delves into the rarity of certain conditions, such as cerebral palsy, and the challenges in early detection. Oster utilizes data from the World Health Organization to establish normal ranges for developmental milestones, offering parents a broader