Rebecca Basham’s “Wrinkles,” now in its world premiere at Diversionary Theatre, is a warm, old-fashioned, three-act family comedy-drama of the sort you don’t see much any more..

Except everybody turns out gay.

Three generations of a nice middle-America family find refreshing strength in admitting finally that they prefer women. This isn’t giving away any key secrets, though Basham’s script is coy about each revelation. That’s what the play is about, after all: Girls get girls.

Rosina Reynolds has directed with sublime assurance and a knack for loaning to each of her admirable actresses a bit of their director’s own laser timing and gallant sparkle without depriving them of their individual artistic personalities.

It’s the 1980s in middle America and Grandma, who raised four children and buried her husband after a half-century marriage, is heading for Florida to join her sweetheart from 1942. The ladies have been writing weekly since and the time for fulfillment, says Grandma with ringing explicitness, has come.

Act I is her coming out to her stunned granddaughter, a defiant if frazzled champion of the New Feminism with a PhD in Women’s Studies, a university teaching slot and a tendency to revert into girlhood.

Act II introduces the middle member, a bright and hard psychotherapist who dismisses her mother’s Florida escapade as a stage, much like the one she herself went through several years back with a girl scout leader. Of course Mom isn’t a Lesbian: that was just healthy curiosity. True the results were so spectacular that Mom has sworn off men, but she insists firmly that she now takes care of herself. What’s she’s wondering is why Grandma’s revelation shocked her daughter into near catatonia. “What’s your issue?” asks Mom curiously.

Of course we have our suspicions (and we turn out to be right) but first there’s yet another scene change – these tireless prop people deserve hearty congratulations – for a Christmas reunion and the last of the confessions (so far) before the huggy final curtain.

This being a play for the gay-Lesbian-bisexual-transgender set, there was much knowing laughter. (“Nuns aren’t gay!” drew a major guffaw.) But it’s a play that welcomes anybody who’s ever been part of a family.

Lisel Gorell-Getz, as the youngest generation, is never really offstage, so she has endless opportunity to shape a curve to her character. This takes a while for her to launch – her early reactions are cartooned -– but she pays off handsomely in the long run, pulling it all together.

Sally Stockton as the senior member probably needs just a bit more exotic something, though her dry, matter-of-fact delivery serves her well, but I wouldn’t want Terri Park to change a thing about her brittle, stylish shrink, so very 80s in her steely self-confidence.

Another comfortable set by David Weiner, appropriate costumes by Shulamit Nelson and deft lighting by Jen Setlow.

Trims won’t hurt but, taken altogether, an impressive premiere.