From "Romeo and Juliet," by way of "Splendor in the Grass," it's downhill to "Endless Love," the new Franco Zeffirelli film about teenage romance. But talk about burning passion -- in this one, the kid sets his girlfriend's house on fire in the hope of getting her attention.

Very young love as an ideal is, of course, more easily sustained when the lovers are thwarted early, rather than tested by time. Zeffirelli did a memorable "R&J," characterized, as this film is, by the poignant beauty of the lovers and rich attention to the settings and adult figures. "Endless Love" has Brooke Shields and Martin Hewitt against backgrounds of plump and cozy, pseudo-Victorian picturesqueness.

But the soul of the film is from that wonderful chesnut, "Splendor in the Grass," in which Natalie Wood and Warren Beatty popularized the concept that sexual activity is a basic daily requirement for the mental health of growing boys and girls.

In this decade's version, the adults have taken over this credo, their motto being "you only regret the things you didn't do." The girls parents in "Endless Love" are satirically portrayed, in some of the film's best scenes, by Don Murray and Shirley Knight -- she in a toned-down version of the artistic-hysteric that Sandy Dennis is currently doing in the play "The Supporting Cast" at the Kennedy Center and the film "Four Seasons." There is a kind of Miss Piggy quality to the way the mother opens her life as a divorcee by announcing "the nouveau moi!"; and the father's new girlfriend, an earnest astrology bug played by Penelope Milford, is a scream. The boy's parents, too, sentimentalize the attachment.

It is evident that everyone in the society agrees that teen-age passion is not only real, but the only real passion, and so the adult reactions are all dictated by jealousy or voyeurism. What spoils the satire is that the point of view of the movie and the events it unfolds take this seriously.

But if you listen to the words, rather than watch the posturing, you understand that the entire thwarting consists of the girl's parent's discovery that the romance is interfering with her health and schoolwork -- when they talk of her "not being able to handle this," they are referring only to sex having taken up her normal sleeping hours, leaving her cranky -- and banishing the boy from the house for exactly one month, until examinations have been passed and the school year is out.

This is the cruelty that triggers the tragedies brought on by the insanity of frustration. It's so hard to reconcile with the concept of endless, enduring love that the preview audience howled at all the most passionate moments. Sylistically, too, the juxtaposition of satire and schmaltz spills over to what is intended to ber serious.

And the person who seems least convinced of the validity of the passion is Brooke Shields, who looks ravishing but is most charming when she's childishly affectionate or aloof -- thus blithely making her partner, with his burning eyes, look demented. One begins to feel that making her forgive arson and worse in the name of true love is forcing the naivete of adults on a sensible child.

ENDLESS LOVE -- At the Aspen Hill, Avalon 1, Beltway Plaza, NTI Marlow, NTI White Flint, Roth's Tysons Corner and Springfield Mall.