Get the fuck out!

No seriously, do I really have to?

I was thinking about this with my re-write of Untitled 4. I wrote the outline and back-story for the characters, and started writing the opening scenes. One thing that has become clear is one of my characters seems to have a bit of a foul mouth. I didn't deliberately do this, he just seems to open his mouth and the bad language comes out.

Will this limit the opportunities for this screenplay? Should I make it as family friendly as possible, or will a reader see through the language knowing it can be toned down in a later draft it he is looking for a family film?

Please advise.