When Minnie Driver inadvertently slaps David Duchovny, it’s endearing.

Not that Duchovny is making any untoward advances in the Bonnie Hunt comedy “Return to Me,” which opens today. In the film, he’s a grieving widower and Driver is the woman who, unbeknownst to both of them, is the recipient of his wife’s heart.

Driver is trying to hide the scar as Duchovny is arranging a coat on her shoulders. Pow! He gets one across the face. The slap is actually a refreshing one; it harkens back to the good ol’ days of romantic comedy, when men were bumbling but well-meaning and women were clever and quick with snappy comebacks and their hands. True passion funneled into pure romance and delicious wit.

Romantic comedies are on an upswing. “Return to Me” joins a warm-weather flood of romantic comedies that follow in the wake of alien love (“What Planet Are You From?”), teen romance (“Whatever It Takes”) and sex-crossed lovers (“The Next Best Thing”).

Coming up, the love triangle gets religion in Edward Norton’s “Keeping the Faith.” Norton plays a priest, Ben Stiller a rabbi and Jenna Elfman is their childhood gal pal all grown up. Headed this way from Australia is “Me Myself I,” about a thirtysomething woman sulking about singlehood when she meets up with her married self who disappears, leaving her with a husband and three kids. This summer, Amy Heckerling goes from bringing love to “Clueless” high schoolers to “Loser” college students. The movie stars Jason Biggs (“American Pie”) and Mena Suvari (“American Beauty”).

The interesting thing about today’s romantic comedies is that their romances have become more old-fashioned, more chaste, than ever. At one point, the romantic comedy genre looked as if it would become a casualty of the sexual revolution. But in the movies, love never dies.

“I would say romantic comedy is what Hollywood does very well right now,” says Henry Jenkins, director of Film & Media Studies at MIT. The genre triumphed during silent movies, the Depression era and the ’50s (remember those Doris Day-Rock Hudson movies?). Now, “we’re in the fourth golden age for romantic comedy.”

Lovely leading ladies

Romance has always been part of the movies “The Classical Hollywood Cinema” calculates it was the main plot for 85 percent of all Hollywood films before 1960. Kathleen Rowe Karlyn, author of “The Unruly Woman: Gender and the Genres of Laughter,” points out, “the form is remarkably resilient, and it just doesn’t go away. It’s been around since before Shakespeare, it’s been around since before the Greek drama.”

But one reason for the success of romantic comedies is engaging female performers, says Jenkins, who co-edited the anthology “Classical Hollywood Comedy.” Cary Grant and Clark Gable might be all that, but they’re nothing without Katharine Hepburn and Claudette Colbert. Today’s powerhouses are Meg Ryan and Julia Roberts, who have a “balance of playfulness and seductiveness, intelligence and glamour, professional competency and emotional vulnerability, charm and grace.”

All are qualities that come into play to shake up the genre’s boy-meets-girl formula.

There’s girl meets boy (“Sleepless in Seattle”), boy meets boy (“Jeffrey”), girl meets boy’s brother (“While You Were Sleeping”), gay boy meets girl (“Object of My Affection”), boy meets girl but then meets a boy he likes better (“In & Out”).

Celluloid abstinence

Despite the sexy variations, Hollywood can be positively prudish when it comes to romance. Instead of resisting sexual passion, modern romancers often avoid it. Screenwriter/director Nora Ephron has become a master at keeping the sexes apart: Ryan fell in love with the radio plea of Tom Hanks in “Sleepless in Seattle,” and the two cyberbonded in “You’ve Got Mail.” When Billy Crystal and Ryan finally gave in to sex in “When Harry Met Sally ” (the movie that revived the genre), it nearly ruined not only their chance at love but a decade-old friendship.

“Contemporary romantic comedy has indeed become more conservative, seeking the forms and delicate libidinal glow of ’30s comedies,” notes Bruce Babington, a University of Newcastle (Australia) researcher and contributor to “Terms of Endearment: Hollywood Romantic Comedies of the 1980s and 1990s.”

So is all this skirting around sex postmodern prissiness or liberation? “It’s definitely an obstacle in doing a romantic comedy, but it’s more an obstacle in the mind of Hollywood. There’s no saying an intrinsic relationship isn’t interesting and comic just because they’ve consummated,” Jenkins says.

Babington though, sees Tinseltown’s view of love as “ultimately realistic I don’t think myself that Hollywood’s keeping apart’ contrivances are conservative, except in the sense of conserving romantic love.”

The gay blade

Ironically, celluloid abstinence might explain the popular gay angle. Now that Hollywood is seriously courting female and gay markets, what better way to recapture that glorious man-woman tension? Joan Cusack might have run screaming in a “heterosexual crisis” from Kevin Kline when he admitted he was gay, but Jennifer Aniston, Julia Roberts, Helen Hunt and Madonna preferred dishing with their best friends, who happen to be gay men. They give fashion advice, love to dance and are not sexually demanding. That may be the most permanent relationship a gal can get in an age of serial monogamy.

More ironically still, gay characters have had a lot of success in this most traditional genre. “Since the late ’80s, there have been films that have tried to sort of look at homosexual couples and fit them in the same sort of patterns of romantic comedies for heterosexual couples,” says Thomas Wartenberg, who wrote “Unlikely Couples: Movie Romance as Social Criticism.” “Laughter humanizes gay people, it works against prejudice.”

Notably, straight actors starred in the popular gay romances “Jeffrey” and “In & Out.” So far, Rupert Everett is the only out gay actor to reach leading-man status in the tradition of, well, Rock Hudson

Still, in the way romantic comedy used to challenge class differences, it has somewhat done the same with gay relations. “In the classical period, social class was always the external social obstacle,” Karlyn says. “Today, it’s interesting how romantic comedy is trying to use the structure to bridge other differences.”

“In people’s consciousness, class isn’t the big issue anymore,” Wartenberg agrees. “The big social movements have been around issues of gayness, identity, ethnic identity.”

Making the marriage bed

In the old film days, a relationship’s consummation was the marriage scene, the happily-ever-after, fade-out-and-show-the-credits moment. More often than not, today’s romantic comedies end with the couple agreeing only to give their love a chance. Words like “eternity,” “forever” and “always” rarely come up.

“There is a problem about the endings of these films,” says Virginia Wexman, author of “Creating the Couple: Love, Marriage and the Hollywood Performance.” “Hollywood is beginning to look at new avenues for romantic fulfillment, and there is a real uncertainty to what should happen to these new avenues.”

In “My Best Friend’s Wedding,” Roberts did end up at a wedding, but as a guest. “Julia Roberts ends up dancing with a gay man,” Wexman says. “What does that exactly mean? What kind of closure is that?

“Traditionally, romantic comedy in its original Shakespearean form has the young lovers kind of take over from an older, less forward-thinking generation. A lot of it has to do with the promise of future generations, of procreation and life goes on.”

But instead of relationships for the good of society, we now get relationships that are just good for those involved in the relationship. That’s love as therapy, Wexman says. “How can I find someone to fulfill me?'”

In the ’50s and ’60s, Cary Grant and Clark Gable had to persuade the independent Doris Day to get married; she didn’t need a husband to complete her personality. Yet, some 30 years later, Tom Cruise gave Renee Zellweger the second most-famous line of “Jerry Maguire”: “You complete me.” And love literally was therapy for Jack Nicholson, the obsessive-compulsive who started popping his pills again in “As Good as It Gets” because, as he told a melting Helen Hunt, “you make me want to become a better man.”

Last frontier

While Hollywood has at last acknowledged the genre’s gay presence and following, it’s not ready to swing open the doors. Lesbian characters and even lesbian actresses still haven’t strayed from independent cinema; Anne Heche said in a recent NPR interview that, after she went public with her relationship with comedian Ellen DeGeneres, it was only Harrison Ford’s insistence that kept her in the screwball romance “Six Days, Seven Nights.”

Another frontier is interracial romances, usually relegated to drama, tragedy and maybe martial arts movies. After all, it wasn’t so long ago that big star Denzel Washington refused to kiss big star Julia Roberts in the action-drama “The Pelican Brief” because he didn’t want to spark any racial issues.

Even surmounting those romantic obstacles seems inevitable in a genre that has managed to adapt to the times, all the while laughing at love.