What do you do if a parent asks you whether or not to be worried by the sexualised behaviour her child is showing? Should you be worried about a two-year-old boy who puts on his mother’s underwear? How do you know which behaviour is normal, whether it is just exploratory play whether it is based on observing adult sexual activity or videos, or whether it is a result of participative sexual abuse? Should you reassure and ignore, or should you take it seriously enough to ask social services or a community paediatrician for a further opinion?