THIS good-natured and affable yet fairly forgettable rom-com follows a lesbian couple, 40-year-old lawyer Olivia (Lucy Punch) and her younger painter girlfriend Alex (Faye Marsay), who are both happily in love despite their age difference.

But niggling away at Olivia is her need to start a family, with her biological clock ticking away as she looks on with a mix of love and envy at her younger partner’s more carefree existence. Fans of this sort of film won’t be surprised to find out that Alex isn’t quite ready for that big responsibility.

In a huge betrayal of trust, Olivia decides to go down the road of artificial insemination without Alex’s permission. After she finds out about it, Alex has a drunken one-night stand with neighbour John (David Tennant) and ends up pregnant, too. But despite tensions putting a rift in their relationship, they decide to patch things up and be pregnant together, with John sticking around to help out.

The feature debut from writer and actress-turned-director Daisy Aitkens is a breezy, fun watch that’s quick to put a smile on your face, almost at the expense of dramatic heft or realism. It never quite digs deep enough to make an impact on its themes of the joy-meets-fear of impending motherhood and heteronormative ideas of what a relationship and raising a child should be. It also struggles to juggle the light-hearted tone with the more serious, tragic narrative turns.

Punch is a terrific comedic actress capable of pushing giddy ridiculousness to the borders in all manner of roles but she’s playing nicely against type here as the straight woman, so to speak, of the pair.

Marsay makes for a nice yin to her yang, despite being somewhat trapped inside a pedestrian “starving artist” role that doesn’t quite convince due to the feeling that no-one in this middle-class existence wants for anything. Similarly Tennant makes the over-the-top role of John work with his natural charisma and brash charm.

It fits very much into a mould that has soared to box office heights with the likes of the Bridget Jones series but it goes through the motions rather than breaking any new ground. However, approaching it on that level is probably the best way to enjoy it; it’s a film that makes likeability seem like an easy thing to achieve.

Aitkens sustains a sweetly light-hearted approach – all bright colours, peppy pop soundtrack, smiling hugs and a sitcom-esque ethos that, despite how things might seem at the time, everything will probably turn out alright in the end. Ultimately this is a pleasantly distracting, if not exactly heavyweight, look at the ups and downs of 21st-century relationships.