"Weird Science" is the latest effort of one-man teenpic factory John Hughes, writer/director of such celebrated movies as "The Breakfast Club" and "Sixteen Candles," and it reveals just what a stale hack he was all along. Hughes has an ear for the baroque creations of teen-age speech, and for this ability (which is to say, the talent of a tape recorder), plus a certain gloss of pretension, he is acclaimed as a serious filmmaker. He is, in fact, simply a higher order of panderer.

The movie is the latest in the "Wouldn't it be neat if . . .?" school of movies. Wouldn't it be neat if two high-schoolers, Gary (Anthony Michael Hall) and Wyatt (Ilan Mitchell-Smith) could feed a computer with old Playboys and create the perfect woman? And wouldn't it be neat if that perfect woman, whom they christen Lisa (Kelly LeBrock), had the power to give one a Porsche and the other a Ferrari, just with a snap of her fingers? Or turn Wyatt's mean big brother, Chet (Bill Paxton, who takes more joy in his performance than we do), into a four-foot frog?

Hughes infuses the movie with the "After-School Special" moralisms that are supposed to indicate that he Takes Kids Seriously. "When are you going to learn that people like you for what you are, not for what you can give them?" Lisa asks her creators. By the end of the movie, that's when! Just around the time, in fact, that they don't really want the perfect woman -- they'd prefer the girls next door. The very premise of the movie -- wouldn't it be neat to create a sex object? -- is discarded almost immediately, as Lisa, with one eye on the precious PG-13 rating, becomes less demimondaine than den mother. And beauty, as usual, is a badge of some kind of defect. When are great-looking women going to unionize?

Hall, a talented comedian with a head like a toadstool and curiously unformed features, gives his worst performance so far; at times he plumbs his richest vein -- faked arrogance -- but mostly, he's bugging his eyes in slow double takes, as if Hughes had got him by the thyroid. In his third screen role, Mitchell-Smith suggests a kind of charm unique among kid actors -- with his strangled monotone and vaguely nauseated expression, he's adolescence as perpetual depression, life defeated at the threshold -- but he's not asked to do much but double-take, either. And LeBrock, a plasticene beauty with sudsy curls and sensuous lips as thick as bicycle tires, manages to look terrific without being sexy, mostly because she opens her mouth. She looks like the cover of Vogue and sounds like Sebastian Cabot.

Hughes supplies enough car chases, loud rock music, masturbation jokes and youthspeak (to break wind, for example, is to "float an air biscuit") to ensure breaking even with the youth audience, which only says that what "Weird Science" is really about is the Dismal Science -- no surprise. What can you say about a movie whose funniest gag consists of the boys strapping cumbersome orthopedic brassieres on their heads? Like the rest of America, I suppose, they have Madonna on the brain.