"Mermaids" and "Life Is a Long Quiet River" are coming-of-age pictures about independent youngsters who, in their own way, manage to break the bonds of their chaotic upbringing - and both films also have to do with the influence of "vulgar" lifestyles on middle-class values.

It's also interesting to note that, as usual, coming of age means young teen sex, cinematically sanctioned because one film is set in the early '60s and the other is French.- "MERMAIDS" is being touted as the new Cher film - it's her first movie role since she won the best actress Oscar for "Moonstruck." But this movie is more about her character's daughter, played by Winona Ryder.

And therein lies the film's main dilemma. When it's about eccentric single-Mom Mrs. Flax (Cher) and her tentative romance with shoe salesman Lou Landsky (Bob Hoskins), it's funny, warm and most compelling. But when it's about Mrs. Flax's 15-year-old daughter Charlotte (Ryder), who is torn between the call of her hormones and a strong desire to be the antithesis of her "loose" mother by becoming a nun - despite being Jewish - it tends to founder. And Ryder's intrusive, heavy-handed voice-over narration doesn't help.

The setting is 1963, and Mrs. Flax is a free spirit with two daughters (young Christina Ricci as swimming champion Kate is the other). She's terrified of commitment - a nice twist on the kind of angst usually relegated to male characters - and her solution to every problem with a man is to move. She chooses her destination by pointing blindly at a map.

Early in the film, the trio heads from Oklahoma to a small town outside Boston, where Mrs. Flax catches Lou's eye and Charlotte develops a crush on Joe (Michael Shoeffling), the caretaker of the local convent. The latter doubles Charlotte's internal struggle, a conflict between her lust for Joe and her longing to join the order.

Some of this is very funny - when "Mermaids" is on the mark it's a riot - but often it bogs down with pointless set-pieces that seem to go nowhere and suffers from an ending that feels contrived and overly sentimental. (And I'm not sure a 15-year-old's sexual encounter should be treated like a badge of honor.)

There is some compensation in the form of a few big laughs and the exquisite performances - especially from Cher and Hoskins, who work up some real chemistry between her hedonistic pursuits and his down-to-earth desire for a family. Too bad they tend to get short shrift.

Director Richard Benjamin's first two films, "My Favorite Year" and "Racing With the Moon," were wonderful character comedies. Lately, however, they have given way to formula clunkers like "My Stepmother Is an Alien" and "Downtown." "Mermaids" is somewhere in between - but it's hard not to feel this one had the potential to be much better.

It is rated PG-13 for sex, profanity and vulgarity.

- "LIFE IS A LONG QUIET RIVER" is sort of a straight version of that Bette Midler-Lily Tomlin comedy "Big Business," pre-pubescent-style.

This French satire is a compendium of sequences loosely telling the story of how a vengeful nurse's spiteful act has repercussions for two families - one upper middle-class and one poor - some 12 years later.

The nurse switches newborns because she's angry with the doctor who delivered them - they're having an affair and he treats her quite badly. Then, 12 years later, when his wife dies and he refuses to marry her, she informs the families of her earlier action.

So the young boy in the poor family, who has become a smoking, drinking petty thief, is taken in by the well-to-do family, a strict, straight-laced Catholic brood. The result is rather predictable chaos.

Some of this is moderately amusing, some rather coarse, with a great many characters, most of whom are skimmed too superficially. The result is a movie with something to say about genetics vs. environment, but which doesn't say it particularly well.

It is not rated but contains sex, nudity, profanity, vulgarity, violence and drugs.