This gentle, low-key comedy-drama laudably tries to sketch the outlines of a unique relationship, between a surrogate and the single biological father of the child she’s carrying, which itself could never have existed until the advent of IVF. Surrogacy may have been around for a while, but as a species and a culture we’re all still working out how to do it on a social-emotional level, and that proves a reasonably fertile ground for a comedy of modern manners. That said, Together Together suffers a little from being too polite, as a comedy it lacks snarl, and as a drama it lacks, well, event. Nothing much really happens – but maybe that’s the point.

Millennial barista Anna (Patti Harrison) has signed up to be a surrogate because she needs the money to complete the university degree she never finished before she got pregnant. She gave up that first child for adoption, and plans to hand over the next one as soon as he or she is born to fortysomething software developer Matt (Ed Helms), the biological father who conceived the foetus with an unknown egg donor. The two didn’t know each other before at all, but since they both live in Los Angeles and seemingly don’t have that much to do, they end up hanging out together a lot. At first it’s just dinner (he tries to micromanage what she eats), but before long they’re redecorating the nursery together, throwing baby showers, and binge watching Friends, which Anna professes to have never seen.

Now, I’m no expert – having never been in this situation – but even the most casual observer can see that either the two really haven’t set their boundaries properly or they’re falling in love. The script, by director Nikole Beckwith, can’t really make up its mind and instead settles for a lot of wan jokes about the two main characters’ generational disparity, which land softly. Even so, the bit where Anna and her omnisexual colleague Jules (Julio Torres, a zing machine) despair over the prospect of the kid turning out to be another straight white guy (“He’s going to make a podcast,” sighs Anna, “about Reaganomics”) is quite funny. The end result is well meaning but wussy, especially when compared (perhaps unfairly) to the recent, much sharper drama The Surrogate which only came out a few months ago.

• Together Together is released on 20 September on digital platforms.