We were swimming yesterday and I took PB, all of 19 months old, into the mens for a shower to wash the chlorine that had caked on. Once I dried her off she happily ran around naked for a while in the mens. Age 19 months, that's OK. Age 19, that's not OK (if it's my daughter). So clearly there's a line to be drawn - at what age does it come unacceptable for opposite sexes to run around naked in change rooms?

_{And at what age does it become acceptable again?}