Are japanese kids aloud to curse in front of theyr'e parents or authority?

Question:

just curious, because a friend told me that they did..

Answer:

allowed*
their* (they're = they are)

Japanese as a language doesn't have cuss-words in it the way that other languages do. Sure they have words like "kuso", but it is more like saying feces (faeces) than any other meaning. However, Japanese kids tend to be well enough behaved that this is a moot point.