It is the normality of it all that strikes you. Jeroen van der Ven and Vanja Maria Godee play an ordinary married couple. He is a truck driver who works part-time in a slaughterhouse. She looks after the kids. They grew up in a Mennonite community but, the way they tell it, even that seems unexceptional.
They are humble and undemonstrative. That is why when they meet a certain Dr Money, they are overawed by his fancy Harvard education. He is an eminently qualified man; neither of them went to university and they have no reason to doubt him. Far from it. He offers them a solution to their problem: what to do with their son Bruce who, in a botched medical procedure, has lost his penis?
That is another event over which they have no control. In this gripping production by Carly Wijs, they appear to show no rancour, only distress. What Dr Money offers is the option of bringing Bruce up as Brenda. All it will take, he assures them, is hormones and a dress. In the debate between nature and nurture, he opts decisively for the latter. If they bring her up as a girl, a girl she shall be.
Which would possibly be fine if the child felt the same way. But, in this true 1960s story, Brenda is unhappy in her skin. She does not know her own history, but senses something is wrong. The dislocation even seems to rebound on to her twin brother, Brian, who stumbles towards drug abuse and psychosis.
And although Boy seems to do no more than tell the story, much as Wijs did with the 2004 Beslan school siege in Us/Them, there is something in its clean, candid narration that makes it compelling. Accompanied by a playroom’s worth of cuddly toys – symbols of a childhood knocked off course – the actors show how easily two devoted parents can be caught off guard by the professional world.
And at a time of heated discussion about gender, it is fascinating to hear a story about a child not only rejecting an identity that has been imposed on them but also wrestling with the behaviour society decrees as “normal”.
Boy is at Summerhall, Edinburgh, until 28 August.