There was a time when the average sci-fi screen heroine spied an extraterrestrial, screamed and took off in a sprint, usually while wearing high heels. Today's woman has a more liberated outlook -- she invites the alien into her bedroom.

Take "Starman," the John Carpenter film about the love that develops between alien Jeff Bridges and his Earthling hostage, Karen Allen. Intergalactic romance was never so sweet. Bridges touches Allen's heart by bringing a deer killed by a hunter back to life. She introduces him to the wonders of Dutch apple pie with whipped cream. She also helps him discover the pleasures of lovemaking, and is left with a star-baby growing within her.

The sandy-haired, handsome Bridges is never seen in his alien form. We don't know if he's tentacled, crustaceanlike, gelatinous or as wizened as E.T. No matter. Their baby, he gently assures Allen, will look human.

Well, he's one heck of a nice . . . uh, alien. But it wasn't always so with these folk. Filmed under a mushroom-shaped cloud of paranoia, sci-fi films in the '50s and '60s urged moviegoers to "Watch the Skies!" Collectively, the story lines also implored them to watch their women. Nine times out of 10 -- or so it seemed -- aliens had women as well as invasion on their nasty minds.

Oftentimes their planets had been polluted, rendering their female creatures infertile. Naturally, they headed toward Earth for what can only be perceived as a most unnatural union. Films of that era weren't too specific about the results of such courtships -- nor, for that matter, about how the mating process could occur, given the unique physical properties of some of the aliens.

Logic gave way to the impact of one of the decade's most potent sci-fi images -- that of a shapely young woman being carried off or menaced by a creature. Whether the victims were ponytailed ingenues in flouncy skirts or peroxide blonds in tight dresses, the mostly male audiences rooted for their rescue just as surely as they savored the (eventual) salvation of America from alien tentacles.

In "I Married a Monster From Outer Space" (1958), Gloria Talbot is a young bride who makes a wedding-night discovery that something's not quite right with husband Tom Tryon. For one thing, he's suddenly coolly detached. Another warning sign comes when she glimpses his startling transformation into a creepy being with masses of exposed arteries bulging from his head. Little wonder that she recoils in terror when she learns that his dying planet is in need of fertile women to produce children. (When she asks, "What kind of children," the ominous reply is, "Our kind.")

Aliens, it seemed, would do anything to cure their population woes. Death rays and robots are dispatched to Earth when the planet Mysteroid runs out of young women in "The Mysterians" (1957). In "Night Caller From Outer Space" (1965), John Saxon uses newspaper classifieds to meet potential "brides" for one of Jupiter's moons. Earth girls are kidnaped in "Frankenstein Meets the Space Monster" (1965). No synopsis is necessary for "Mars Needs Women" (1966).

To be sure, there has been a spate of films about alien femmes who, like their male counterparts, are in need of child-bearing assistance. Descended from the survivors of Atlantis, who colonized one of Jupiter's moons, the "Fire Maidens From Outer Space" (1956) welcome explorers from Earth by declaring, "With your help, gentlemen, New Atlantis will rise stronger than ever!"

The Earthmen of these films generally espouse a take-charge attitude -- especially in matters of the heart. Still, they don't faint (as most Earthwomen do, or did then) at the first indication that they're expected to beef up the population. That's because most alien females are of the lovely-to-look-at variety -- occasional green skin or predilections to blood-sucking tend to be ignored.

The "Cat Women of the Moon" (1953) prance about in revealing tights. The followers of Zsa Zsa Gabor in "Queen of Outer Space" (1958) wear flowing Grecian-type garb. "Invasion of the Star Creatures" (1964) features a pair of long-legged, other-worldly beauties.

Just how and when aliens took on nobility is a story in itself, though Eric von Daniken's 1969 best seller "Chariots of the Gods," which suggested that good aliens predated man's existence on earth, seems a turning point. Steven Spielberg completed the process of turning fright to fascination and, finally, to fondness.

Starry romance was a natural progression, though it wound up confusing the Man of Steel (who lost his superpowers after losing his virginity to Lois Lane in "Superman II"), and went the metaphysical route in "Star Trek: The Motion Picture." The romance in "Starman" is much more down to Earth. But would it work if the alien in question weren't pinup material?