I mean…dam, Marty.
Hey kids! Let’s watch a show–
A movie your dad and I both know.
It’s kid-friendly time-traveling fun,
With a quantum-modified DeLorean!
Imagine my delighted surprise
At the potty-mouth on that McFly.
More education than we bargained for
With that god-damned f$#% capacitor.
I am the last person to get after someone for their language, unless I physically made that person. I firmly believe that there are no bad words, just inappropriate times to use them, but when you’re this many (holds up five fingers), every time is the inappropriate time.
We did not remember the extent or the creativity of the swearing in Back to the Future. Have my kids heard some of it? Sure. Usually not in a sanctioned venue that Mom is encouraging them to be a part of. I told myself afterward that it’s better that they hear it at home. Wait. What? Shit, that isn’t right, is it?
YOU SHOULD BE HAPPY 
NOW I remember this feature from seeing this movie in the theater; I would have been about 7 or 8. May have to rewatch before I introduce to this kids, but my words policy is similar:
“Uh oh, he’s using language!”
“Son, while I agree that word is generally not appropriate for conversation, if you are ever being chased by a dinosaur who has just eaten your friends, you have my permission to use it.”