Exploration of sexual identity makes compelling theater

It’s a 20th-century horror story: The parents of infant twin boys are told that their sons must be circumcised immediately — to address a medical emergency rather than for the usual religious or cultural reasons.

The first circumcision is handled so badly that the child’s penis is mutilated and must be removed entirely. The second child’s circumcision is postponed; before it can be rescheduled, the emergency resolves itself.

The parents are horrified. Then a doctor who believes that gender identity is determined by socialization rather than anatomy and biology advises them that the best course of action is to raise the penisless boy as if he had been born female.

Socialize the child as a girl, do a little sex reassignment surgery now and then complete the physical makeover when the child — renamed Samantha — becomes a teenager.

And if Samantha’s parents allow the doctor to use the twins as case studies in a research project, he and his hospital will pay for everything.

Samantha grows up unaware of what was done to her but with a very strong feeling that something isn’t right. Welcome to The Actors’ Group production of “Boy.”

The challenging but compelling drama is playwright Anna Ziegler’s fictional take on the real-life tragedy documented 17 years ago by John Colapinto in a book titled “As Nature Made Him: The Boy Who Was Raised as a Girl.”

Zeigler’s play received good reviews when it ran off-Broadway early last year. TAG premieres it in Hawaii as excellent thought-provoking adult entertainment.

Randall Galius gives an engaging, multilayered performance as he alternates between playing Samantha as a child and preteen, and Adam, a man in his early 20s. Jaime Bradner makes her TAG debut a memorable one with her charming portrayal of a young woman who finds Adam odd but appealing — even though he isn’t pushing her to have sex with him.

Jason Kanda has excelled for years at playing strange and bizarre characters. Here he plays a doctor who takes a very personal interest in the “girl” he is training. It isn’t necessary to know the facts laid out in Colapinto’s book to find the doctor creepy and his motives suspect, but Kanda also makes the man seem seem tragic and even vulnerable.

Hawaii stage veterans Melinda Maltby Purdy and Dann Seki are spot on as Saman­tha’s bewildered but well-meaning parents. Seki is such a pro that he gets a laugh in one scene without saying a word — the expression on his face is enough.

>> “Boy,” by Anna Ziegler; directed by Jim K. Aina; set design by Andy Alvarado; costumes by Chris Valles; lighting by Thomas Tochiki; sound by Kahana Ho. Running time: 1 hour 36 minutes.

>> With: Jaime Bradner (Jenny), Randall Galius (Adam/Samantha), Jason Kanda (Dr. Wendell Barnes), Melinda Maltby Purdy (Trudy) and Dann Seki (Doug)