Medical professionals frequently use developmental milestones, but is our fixation with them having an unexpected negative effect? You’ll soon come across so-called milestone cards if you browse social media feeds for parents: pastel-colored cards with the baby’s age and the first time they tried to sit up, crawl, or walk. Developmental milestones are no longer merely something to celebrate or worry about on social media.

One recent poll, for example, found that around six in 10 US parents worry about their babies meeting their developmental milestones. But few knew what should happen and when. “On a very concrete level, a milestone is a description of a behavior of a child that parents either say their child can do or cannot do,” says Chris Sheldrick, a research associate professor at Boston University who focuses on pediatric screening protocols. He points to the literal meaning of the word itself. In a 10K race, there may be a marker, or “milestone,” at the 5K mark. By definition, no one has passed at the start of the race. By the end of the race, everyone has.

It is essential for parents to understand that developmental milestones are not a competition. They are a guide for healthcare professionals to monitor a child’s progress and ensure that they are developing at a typical pace. In order to use them effectively, parents must be informed and aware of what milestones are expected to be achieved and at what age, but they must also be flexible and not stress over them. Parents should trust that their children will develop at their own pace and not compare their children to others.