When should girls start wearing deodorant? my 7 year-old daughter slept over at her cousin's house and her aunt applied deodorant without consulting me first?

Both girls and boys should start using deodorant when they begin to have body odor that others are noticing. This almost definitely happens by puberty but sometimes occurs at a younger age like your daughter's age.They can use deodorant then but it is recommended that one without antiperspirant is used for the younger children. Also, be sure the child is showering and changing undergarments daily.

Short of a contact dermatitis, your daughter should be unharmed. Deodorant is used when needed, that is when body odor becomes an issue a few years later at puberty. At that time, most teens will select a product that also has an antiperspirant, to ward off dreaded underarm moisture. Let this pass. Let your child know your stance on deodorant for the next time.