From the son's recently degenerated sense of humour, it had become clear that it was time for a "chat". "You can ask me anything you like, " he told his son. The boy grew embarrassed.

"Daddy, " the nine-year-old finally said, "how do lesbians have sex?"

Gina Moxley's Danti-Dan is all about emergent and precocious teenage sexuality, and yet it is impossible to imagine them asking any such thing.

Written in 1995, this play could conceivably have been staged then as almost a contemporary piece. Just before the boom, and before the mass uptake of digital telecommunications, it was still possible to imagine a group of kids whose only cultural references were their immediate environment.

In Danti-Dan, the outside world is represented by a public telephone that doesn't work. The sole cultural reference is to a date at the movies . . . and they didn't even notice what the film was. No references to films (apart from the generic cowboy reference), to music, to TV; no mobile phones; no foreign travel; no real work.

Gina Moxley sketches this world with exquisite touch. She saw, rightly, that setting her play so removed from the cuttingedge of modern culture would allow her to focus on the simple truths of the relationships she sought to portray.

Those characters, and relationships, are eternal ones: the precocious teenage girl and her bullied sidekick; the older girl trading intimacy with her boyfriend for the promise of marriage; the boy lost in his obsessive fantasy world. The young cast, mostly Gaiety School graduates, do a tremendous job.

Sarah Greene must be singled out: her uncomfortably adult teenager is an extraordinary mix of sly knowingness and underlying innocence, of aggression and fear. David Horan directs for a remarkably easygoing, natural pace, and his actors flourish.

The mid-1990s was some time in Irish theatre. Conor McPherson, Marina Carr, Enda Walsh and Martin McDonagh emerged with force, soon followed by Mark O'Rowe.

Meanwhile, London was shopping and f***ing, as Mark Ravenhill and Sarah Kane reinvigorated British theatre.

There is the sense of a paradigm shift at that time, and Moxley can be seen standing at the edge, looking back, wobbling.

She stands somewhere between Billy Roche . . . whose Wexford plays share a sense of elegy for a lost Ireland, as well as a subtle indictment of the underlying sexual violence in that past . . . and Enda Walsh, whose Disco Pigs takes a couple of Cork kids similar in age to those in DantiDan and catapults them forward into a sordid, violent, intoxicating fantasy world.

At some point in the late 1990s, Irish theatre awoke with a start to the totems of postmodern culture: irony, self-reference and violent and sexual fantasy. It was probably belated but it became near ubiquitous. Moxley reminds us that it didn't have to be that way.

If there is a weakness in her play, it is in the ending, where she takes a step in the direction of the emergent trend and imposes upon her characters an act of sadistic violence. It brings the narrative to a neat conclusion but it undermines the more subtle emotional truth of the play.

So it is perhaps appropriate that neither director nor cast handle this moment well: the death of one of the characters is a contrived plot device and it loses further credibility in an awkward piece of staging. The cast, for most of the play immersed in utterly credible portrayals of kids who are essentially innocent, can't manage such a dramatic loss of innocence.

Better for the play to have left that loss more subtle and more implicit . . . more like the plays that went before, than those that came after, perhaps.