It’s weird to realize that the great playwrights who came of age in New York in the nineteen-sixties and seventies—artists ranging from John Jesurun to Wallace Shawn, Sam Shepard, Mac Wellman, María Irene Fornés, David Rabe, Adrienne Kennedy, and Rosalyn Drexler—are now the elder statespeople of the American theatre. Weird because one never thinks of these writers as “old”; what made them stand out from the beginning was their youthful pushiness and zeal when it came to putting their unique visions of society onstage. Their early scripts continue to work our nerves because they’re meant to: the chaos, bitterness, and crackling moments of absurdity that defined their times are inseparable from the stories they needed to tell. Civil rights, the Vietnam War, and the fight for gay rights and women’s rights no doubt contributed to the sense of urgency. The violence and strife one finds in Shepard’s and Rabe’s dialogues about the post-Eisenhower-era family, for instance, call into question not only the idea of home but its presumed head: the great white father.

That father—the custodian of cruelties—is central to Taylor Mac’s “Hir” (sensitively directed by Niegel Smith, at Playwrights Horizons), a play that harks back to a time when politically driven narratives were the rule, not the exception. Actually, Arnold Connor, a fifty-something father (played, with beautiful timing, by Daniel Oreskes), predates Rabe’s and Shepard’s weak blowhard dads. He’s a sadder, muted brother to Edward Albee’s Daddy in “The American Dream” (1961). But Arnold doesn’t wear suits or cardigans—the kind of “Father Knows Best” costuming that would tip us off to his role and what to expect from it. Instead, when we first meet Arnold, he is dressed in a loud, frilly nightgown, his face covered with gobs of makeup, like a third-rate clown’s. Standing unsteadily amid piles of household debris—clothes, appliances, plastic containers, a makeshift bed—Arnold hardly knows how or when to move without instructions from his wife, Paige (Kristine Nielsen).

These she provides with condescending relish from the start of the strange spectacle, which the couple’s son Isaac (Cameron Scoggins), a marine who hasn’t spoken to his family for a year, finds as bewildering as we do. Isaac has been discharged from the military with post-traumatic stress disorder (though he never admits it). When on duty, “I,” as he’s sometimes called by his family, works in “mortuary affairs”: “I pick up guts. Exploded guts.” As death’s janitor, Isaac is always on the lookout for slime, the real and metaphysical messes that testify to the fact that life can change or end in an instant. Has his life with his parents—his life as a son—ended, too? His home is no longer recognizable to him. Paige tries to mother Isaac, but he doesn’t understand her language, let alone her intentions. He knows that Arnold had a stroke, but why is she feeding him estrogen? Tranquillizers?

Isaac: The doctors prescribed him estrogen? Paige: Oh, God, no. The doctors prescribed him poodle-diddle-wing-wang. The estrogen’s extra. . . . It keeps him docile. Isaac: He’s gonna grow tits. Paige: Grammar! Isaac: He’s going to grow tits. Paige: Language! Isaac: He’s going to grow breasts. . . . You can’t give him, Dad . . . men estrogen.

Oh, yes, you can. Arnold’s on this odd cocktail because he’s violent. Paige explains that when Isaac left home (he enlisted because he couldn’t afford college or find work) Arnold lost part of his audience. Other things were taken away from him, too: his job at Roto-Rooter, for example. The company got tired of fielding calls about this angry racist plumber guy and replaced him with a young Asian-American woman. With his power in the world dwindling, Arnold became more of a dick at home. “He doubled down on Max and me,” Paige says, referring to their teen-age son (energetically played by Tom Phelan), who used to be their daughter, Maxine. “Three times I had to take Max to the emergency room.”

But Maxine didn’t let Arnold’s rages deter her from buying testosterone online so that she could become the boy she felt herself to be. And now Arnold’s meds—including the estrogen that Paige mixes into his “shaky-shake”—have made him docile in the way that Paige likely was for most of her marriage. She and the world are different now. “It used to be you could be a mediocre straight white man and be guar-anteed a certain amount of success,” she says. “But now . . . the darkies have come. And the spics. And the queers. And those backstabbing bitches waiting to get at the mediocre straight white man the minute it becomes known he is barely lifting a finger but thinking he is lifting the world.”

Change, physical and otherwise, is at the center of “Hir.” And the most extreme evidence of that change is Max. Paige’s delighted descriptions of how the “ ’mones” are affecting Max’s body make Isaac retch, as does her wish to sell the family home and move on. Isaac is the straight man in his family’s painful comedy. (He is also the artistic progeny of David Rabe’s damaged Vietnam veterans.) He can’t deal with having the patriarchal rug pulled out from under him. Arnold was, to some extent, his ideal of manhood, and what happens when our ideals are rendered impotent? Paige, on the other hand, is enthralled by the transformations around her. Freed from her traditional role—if Arnold wants a neat cupboard, he can tidy it up himself—she has become, by the end of the first act, a warrior for change. She refuses to show Arnold the compassion that Isaac feels he deserves; she will not, she says emphatically, “rewrite his history with pity.” Before the tables turned, Arnold wouldn’t have, either.

In recent years, a number of young playwrights—Branden Jacobs-Jenkins and Young Jean Lee come to mind—have taken their critical shears to the white-male-dominated family living room that was so prevalent onstage and onscreen when they were growing up. By chopping apart that convention, Mac, like Lee and Jacobs-Jenkins, isn’t so much remaking the world in his own image as he is addressing subjects that remain, remarkably, underplayed on the American stage: what bodies mean and what stories women are allowed to tell or perform. “Hir” has a lot of ideas—necessary ideas, especially when it comes to flinging open closets in the “trans” world—which spill over the edges of the play, but I wouldn’t take much out in order to make the show dramaturgically tighter or easier to absorb. The rudeness of its form is part of its power: you can’t build a clearer future without making a mess of the past.