Playing doctor" is a phrase used colloquially in the western world to refer to children examining each other's genitals. It originates from children using the pretend roles of doctor and patient as a pretext for such an examination. Nevertheless, whether or not such role playing is actually involved, the phrase is still used to refer to any similar examination
Playing doctor is considered by most child psychologists to be a normal step in childhood sexual development between the ages of approximately three and six years, although it can be a source of discomfort to some parents, when they discover their children are engaging in such an activity. Parenting professionals often advise parents to view such a discovery as an opportunity to calmly teach their children about the differences between the sexes, the importance of modesty, and respecting the privacy and bodies of other children.
Adults also use the phrase facetiously in similar reference, to refer to adult sexual activity.