The crisis for the couple at the heart of “Cowboys” begins when their son, Joe (Sasha Knight), expresses his desire to transition.

In this Western-influenced family drama, the father, Troy (Steve Zahn), is happy to acknowledge his son’s identity, but Troy’s scatterbrained sweetness makes it hard for his wife, Sally (Jillian Bell), to see his support as anything more than indulgence. At home, Sally enforces girliness, and she wins custody when she and Troy separate.

Joe begs his father to take him away. In response, Troy steals his son from home, and leads him into the woods on horseback. The legal term for Troy’s actions is kidnapping, and Sally calls on the police to help her find her lost family.

The conflicts at the heart of “Cowboys” are timely, coming in a moment when trans children and their rights are at the forefront of American political debate. But the writer and director Anna Kerrigan doesn’t sensationalize her story. Her characters don’t speak as if they were addressing the audience from a pulpit. Instead, she shows Troy, Sally and Joe communicating through their disagreements; she pays attention to what behaviors come out when they are under pressure. This sensitivity grants the film a mellow feel — the understated “Cowboys” lopes, never quite working up the excitement of a gallop.

The observant nature of this character drama offers Zahn in particular the opportunity to expand into new territory. He hasn’t lost the spaciness that once made him a lovable comedic sidekick, but here fatherhood endows that same charm with pathos, even tragedy. He understands and supports his son, but he may not have the wherewithal to make decisions that will benefit them both.

Cowboys
Not rated. Running time: 1 hour 23 minutes. On virtual cinemas and available to rent or buy on Apple TV, Google Play and other streaming platforms and pay TV operators.