Girl X, Citizens Theatre, Glasgow

The National Theatre of Scotland loves to dramatise an issue. Its most famous piece, Black Watch, was a direct response to the Iraq war. The problem with Girl X is that, while the issue is a meaty one, the drama gets lost.

"Girl X" is a fictional 11-year-old with cerebral palsy and the mental age of a five-month-old baby. Her parents want to remove her womb and breast buds so she never reaches puberty, and to treat her with hormones to stop her growing any more. The character is based on the American Ashley X, who was seven when her parents proposed similar surgery.

Robert Softley, an actor and disabled activist who also has cerebral palsy, co-writes and stars. Having discussed the Ashley X case online, he then worked with Belgian dramatist Pol Heyvaert, responsible for NTS's award-winning Aalst, to put the debate on to the stage.

So the adversarial ganging-up of the internet chat-room is boiled down to "the instigator" – Softley in his wheelchair, his words appearing in superscript on the set – versus "the chorus", 15 random folks with opinions. Softley can't accept that Girl X's parents have the right to infantilise her forever, to put her through major surgery to make their lives easier. The chorus vacillates between Daily Mail ranting and patronising sympathy. At one point there is a men-versus-women ding-dong. Hitler is, of course, bandied around. Softley overheats and makes wild suggestions: "Why don't they chop off her head so they don't see her dribble?"

Softley is an engaging presence, funny and persuasive, the opposite of the "crip with a chip" that people assume him to be. Girl X is a revealing discussion of the issues facing the carers of severely disabled children. But it's a debate that fails to develop into anything bigger.

Touring Dundee, 12 April; Inverness 19 & 20 April ( www.nationaltheatrescotland.com)