I thought they made gowns specifically for baptisms? Or is that only for infants?
Babies are generally baptised naked, then clothed in a baptismal gown or outfit. Older children, adolescents and adults are rarely, if ever, baptised in the nuddy anymore. That's why many (but not all) wear some sort of simple white tunic, usually over shorts or a swimsuit before being immersed. But I've also been to plenty of non-infant baptisms where the person wears shorts or a swimsuit for the immersion, then puts on a white tunic afterwards.