AWAY WE GO (15).

Comedy/Romance. John Krasinski, Maya Rudolph, Jeff Daniels, Catherine O'Hara, Allison Janney, Jim Gaffigan, Maggie Gyllenhaal, Josh Hamilton, Chris Messina, Melanie Lynskey, Carmen Ejogo. Director: Sam Mendes.

The tug of war between nurture and nature continues to divide experts in the fields of child development and education.

Are intelligence and cruelty hard-wired at birth, and are we therefore predisposed to certain behaviour before our first glimpse of daylight?

Or does the love and support of the family shape our conduct towards others? In which case, are children from violent or broken homes doomed to repeat the mistakes of their parents?

In Away We Go, an expectant couple contemplate moving halfway across America so that their child will be raised in a safe, loving environment, surrounded by positive role models.

The irony is that the beleaguered parents-to-be are far more emotionally stable and well-equipped to raise their baby than almost everyone they encounter during a madcap road trip scripted by novelists Dave Eggers and Vendela Vida.

After the emotional ‘sturm und drang’ of Revolutionary Road and Jarhead, Oscar-winning British director Sam Mendes (American Beauty) returns to the comedy genre with aplomb, demonstrating a light touch with his dysfunctional characters.

The film opens as it means to go on, with a hysterical bedroom scene introducing Burt (Krasinski) and Verona (Rudolph), who are blissfully happy in their ramshackle cabin.

With Verona six months pregnant, the couple try to find a new place to raise the baby with the help of Burt’s parents Jerry (Daniels) and Gloria (O’Hara), who live close by in Colorado.

The old-timers throw an almighty spanner in the works by announcing they are moving to Belgium before the baby is born, leaving their son and his partner with no support network. So Burt and Verona ponder moving to a new city and kickstart a journey of exploration, visiting old boss Lily (Janney) and her hen-pecked husband Lowell (Gaffigan), who give parents a bad name.

“She’s only 12 and I already know she’s a dyke,” cackles Lily cruelly, referring to her shy daughter, who can hear every stinging word.

Away We Go is an entertaining ensemble piece that paints a vivid portrait of contemporary America and its foibles.

Krasinski and Rudolph are instantly lovable, and we root for them as they come up against overly-officious airline check-in staff and relatives who clearly don’t know best.

The narrative chugs along, covered in a thin veneer of sentimentality, towards an upbeat and life-affirming conclusion.