Common Sense Note
Parents need to know that two versions of this hit were released on home video, one a PG-rated (more deserving of a PG-13, really) edit, mainly on VHS, and a later R-rated DVD that put back a lot of the original theatrical film's harshest gutter language and vibes. Both detail urban gang-style behavior by the characters ¿ even by nominal hero Tony Manero -- with much swearing, fighting, casual and/or animalistic sex (the most disturbing being a gang-rape at the end), and ultimately deadly mischief. Though Tony ends up seeking a healthier path, his family's Catholic religion has nothing to do with it; in fact, his brother, a priest, quits the clergy, declaring that he has no faith anymore.
Even with sheer disco-dance outfits and leotards, men show more flesh than women: Tony flexes before a mirror in briefs, some of his buddies are pantsless while having sex in the back of their shared car. A near-naked go-go dancer is in the background of one scene. Plenty of sexual remarks and challenges ("Are you as good in bed as you are on that dance floor?"). Talk of pregnancy (and marriage) as an unhappy consequence of sex.
The worst is saved for the end of the movie: a gang-rape (though the camera is an anguished non-participant the whole time). Tony and his gang have a streetfight with Puerto Ricans that results in lots of bruises and bandages. Another fight (off-screen) puts one guy in the hospital with broken limbs. One of the characters dies in a fall off a bridge.
In the R version: frequent F-words and C-words, plus racial epithets for African Americans and Latinos. The racial stuff is still there in the PG version, but the S-word is more common.
Tony Manero goes from a delinquent with racist and sexist attitudes to a more mature guy who realizes there are better things and more admirable ways to behave. Along the way there's plenty of bad behavior: cruising for fights with rivals, meaningless sex, drug connections, and nocturnal mischief that eventually kills one of them. The Catholic religion followed closely by Tony's joyless, stifling (somewhat stereotypically Italian-American) family isn't shown to be a positive thing, or even relevant in their lives, and Tony's brother leaves the priesthood because he no longer has faith.
The car Tony and his friends share has a prominent STP sticker, Trojan-brand condoms make a significant appearance, and there's a dialogue reference to Polaroid cameras (and Polaroid's now-forgotten ad campaign featuring actor Laurence Olivier). But it's the soundtrack, practically quadraphonic in its '70s disco-palace tunes that heavily pushes the Bee Gees and other artists.
Drugs / Tobacco /
Lots of social drinking (including while driving) and some drug use, with much talk of "getting high."