This is the time of year when most of us, willing or not, have to face our families. It seems as if an inappropriate auntie, an overstimulated toddler, or a food-flinging feud must fall into every family … and stomaching them is part of the season of forgiveness. But in George Bernard Shaw’s “Mrs. Warren’s Profession,” the irritable old genius maintains that some family fractures can never be mended.

Shaw’s work has lost a little of its original glamour in the unpretentious new production at the Irish Repertory Theatre. It was once a forbidden play about a forbidden subject, but that spice has faded. Now the company, led into battle by Dana Ivey as the infamous Mrs.Warren, relies on humor rather than rage to carry its message home.

Vivie Warren (Laura Odeh) has her bluestockings in a twist: Her mother,an absentee figure for most of her life, is insisting on a visit. Pragmatic Vivie, fond of math and stocks and actuarial accounting, has fallen far from the tree of her loud, vulgar, and oddly charming mother. Mrs. Warren (Ms. Ivey) gallivants about with her friend Sir George Crofts (Sam Tsoutsouvas), running a shady business on the Continent. She’s a jolly sort of scandal – no one even pretends to believe there was ever a Mr. Warren – but she embarrasses her daughter something dreadful.

Unlike a similar mother in Oscar Wilde’s “Lady Windermere’s Fan,” this mama makes no apologies. When she tells her daughter the circumstances that led to her “fall” into prostitution, she places the blame on a sexist, classist Britain. One sister died of lead poisoning, another wasted away as a domestic slave, and poverty suddenly seemed a high price for virtue. Even priggish Vivie embraces her mother’s profession, as long as it seems the outcome of fierce determination and survival skills.

Unfortunately, the now-wealthy Mrs. Warren still hasn’t retired, and she is making other girls into what she once was. When Vivie exposes her mother, she pays a steep price: Her beau, Frank (Kevin Collins), won’t touch a fortune made on young girls’ backs. Where Wilde would have scolded Vivie for her prudery, Shaw makes her into a sad, modern sort of saint. In this diseased world, only by stripping out sentiment and living chastely among her books can Vivie maintain her self-respect.

When “Mrs. Warren’s Profession” first appeared, English censors banned the play for its mentions of prostitution (though the word is never spoken) – and for the implication that every stratum of society must be held to account for it. As always, Shaw was aiming at British hypocrisy: Societal doublespeak veiled the many sins of the upper crust while making the poor suffer for them.Vivie’s actions may seem unnaturally harsh – at one point she thrusts her mother away, accusing her of cheap tears – but in Shaw’s Fabian view, rolling over and accepting society’s degradation of women would have been tantamount to sin.

Ms. Ivey plays Mrs.Warren as a tank, and her upholstered bodices seem capable of repelling mortar fire. It’s remarkable to watch her crumbling in front of her diamond-hard daughter, the only obstacle she cannot crush. In distress, even her language collapses: She whines and yowls, reverting to the lower-class vowels of her youth. Ms. Ivey resists making Mrs. Warren into something noble, and if we can’t quite see the sensuality that lured men to her in the first place, we can certainly see the iron grip that kept them in their place.

Ms. Odeh holds up commendably well in such company, scoring lovely moments with Mr. Collins’s delightfully feckless Frank. And luckily, director Charlotte Moore knows what a crack cast she has and never overpowers it. Gracefully directed on Dan Kuchar’s clever set, “Mrs. Warren’s Profession” never oversells and keeps its audience wanting more. Clearly, Mrs.Warren has taught them well.

Until January 29 (132 W. 22nd Street, between Sixth and Seventh Avenues, 212-727-2737).