Most adult jokes will go over kids heads anyway
IS there some adult humor in this? Sure. Plenty of it. But most will go over young kids' heads. Those the get the joke are already hearing that stuff, and likely SAYING that stuff already. I hate to break it to parents, but it's true. Your 12 year old is almost definitely already talking about the things sung about in Greased Lightning. But the good news is that they are still going to turn out just fine. One thing I find a little disturbing about many reviews is there is plenty of talk about Sandy changing (totally on her own), but not one is upset that she then DEMANDS (in song) that Danny "better shape up" and change for her? (Which is something Danny had been doing the entire movie..changing for her.) Sort of a double standard, saying that it is OK for a woman to demand a man change for her, but not OK to depict a girl who is very old fashioned to want to modernize when she enters a new culture? Bottom line..let's your kids enjoy the music. This movie is not going to give them any sort of sexual deficiencies. Nor will seeing people smoking make them start. If they ask, simply tell them that smoking was MUCH more common, both i the 70s when the movie was made, but especially in the 50s when it was set. But now that we know more about the risks of smoking, it is thankfully decreasing in popularity.