Watching the trailer for the upcoming “The Heartbreak Kid,” it’s hard not to feel a little sad.

There’s Ben Stiller, going through his Ben Stiller motions (likable schlub finds a girl he likes, gets humiliated in a dozen different ways) as the Farrelly Brothers pile on their trademark raunch/strained efforts at achieving something resembling sweetness.

Directors Peter and Bobby Farrelly had their moment back in the 1990s — Woody Harrelson’s one-handed Amish impostor chugging from the milk bucket in 1996’s “Kingpin” and Cameron Diaz’s spiked bangs in ’98s “There’s Something About Mary” are perhaps the two most seminal moments in their gross-out catalogue. Most of their films were celebrations of outsiders making good, but their feel-good sentimentality always felt a little forced.

The trailer for their new effort makes it seem even more by-the-numbers given that it was attached to the front of “Knocked Up” — the new comedy from “The 40-Year-Old Virgin” helmer Judd Apatow, and the first movie of 2007 that I unabashedly loved.

Here’s a movie that delivers more than its share of big belly laughs along with the sort of genuine warmth and heart that you couldn’t squeeze out of a dozen Farrelly efforts.

Apatow is also a champion of the little guy. Here it’s Ben Stone (Seth Rogen), an unemployed 20-something living it up with his friends, all in the same sorry state of arrested development. The closest they come to actual work involves cataloguing movie nude scenes for a Web site they hope to create.

After a night of drinking at a club, Ben hooks up with Alison Scott (Katherine Heigl) and eight weeks later learns that he’s going to be a father. Alison is an up-and-coming anchor for E!, and is way out of Ben’s league, but the two decide to give it a go, starting from scratch to get to know one another as they prepare for their impending parenthood.

Gags involving bodily fluids aren’t needed here. The laughs in “Knocked Up” come from people just being who they are.

Rogen, much like Steve Carrell in “Virgin,” gets to step up from a supporting player to leading man here, and expect to see much more of him. He’s a lovable everyday dude that you can’t help but root for. Heigl stars in one of those young-doctors-in-love shows I’ve never seen, but she more than holds her own.

Alison’s sister and her husband, Debbie and Pete (Leslie Mann and Paul Rudd), provide the couple with a hilarious, “Is this what we have to look forward to?” example of married and family life. Pete doesn’t help matters by describing family life to Ben as being a lot like an episode of “Everybody Love Raymond,” except filled with tension, not that funny and lasting forever.

Many of the laughs come from Ben’s equally affable and aimless stoner roommates (including Jonah Hill, Martin Starr and Jay Baruchel), who effortlessly cut one another down in ways that only affable and aimless stoner roommates can. My favorites: An extended gag involving a bet to grow out a beard that plays out as fast and furious pop-cultural assaults that range from Cat Stevens/Yusuf Islam, the shoe-bomber Richard Reid and Jewish reggae artist Matisyahu, and an unfortunate outbreak of pink eye.

Throw in a memorable rant by Ryan Seacrest and a couple of great new songs by Louden Wainwright (who also has a brief role as Alison’s doctor), and “Knocked Up” proves to be a winning pregnancy comedy that truly delivers.

Address correspondence to Scott Meeker, c/o The Joplin Globe, P.O. Box 7, Joplin, Mo. 64802, or via e-mail, smeeker@joplinglobe.com.