There are no villains in “The Great Reveal,” just well-intentioned but sometimes tone-deaf people moving haltingly toward some kind of understanding.

Valdes is insightful in delineating the ways that unexamined assumptions can cause unintended pain. The play could scarcely be more timely, given how much the gender-identity debate is currently roiling the world of women’s sports, not to mention the ominous choices emanating from Washington when it comes to the rights of trans people.

The word “Reveal” in the title of Valdes’s play is meant to, and does, resonate on more than one level. But Valdes waits too long to let the sparks fly. There’s more drift than there should be in a one-act play. The central tension remains on simmer when it needs to be brought to a boil, resulting in a certain shapelessness.

“The Great Reveal” takes place at a gender-reveal party hosted by newlyweds Lexi (Paige Clark), who is seven months pregnant, and her husband, Christopher (Arthur Gomez), on the back deck of their house, which is bedecked with blue and pink balloons. (The scenic design is by Baron E. Pugh.)

Antonia Turilli and Jupiter Lê.Mark S. Howard

Their guests are Lexi’s brother, Linus (Jupiter Lê), a trans man, and his partner Dosia (Antonia Turilli), a trans woman. There’s a fifth character, but he’s unseen, stubbornly remaining within the house: the father of Lexi and Linus, a toxic sort, to judge by what the siblings say about him.)

Lexi had asked Dosia to bake a cake for the party, and Dosia complied — but the frosting on her finished creation sends a message about her view of the gender-reveal party.

The mother-to-be has no difficulty deciphering that message, and is none too happy about it. Dosia and Linus don’t see gender as being a cut-and-dried matter, as Lexi appears to. (In a program note, co-director Snow describes gender-reveal parties as “a trend which chops up gender-identity to the birth-assigned pink and blue binary.”)

“The Great Reveal” is not the first time a cake has loomed large, symbolically speaking, in a production at Lyric Stage.

Five years ago, the company staged Bekah Brunstetter’s “The Cake,” a comedy-drama that starred the great Karen McDonald as a North Carolina baker torn between her fundamentalist religious beliefs and her innate sense of decency when she is asked to bake a cake for the same-sex wedding of her deceased best friend’s daughter.

Fairly early in the play, “The Great Reveal” is damaged by what’s known in sports as an unforced error.

Even granting that Christopher is anxious about whether he’s up to the challenges of fatherhood (“What if I don’t get any of it right?” he asks plaintively), the playwright’s decision to have Christopher get high turns out to be very ill-advised. Gomez has chosen — or has been directed to — deliver an overly broad performance, often bellowing his lines. It knocks the play off-balance.

Lê’s portrayal of Linus has the opposite problem: He’s too muted. With Clark, the energy level is never a concern, and she brings her customary avidity and ebullience to her portrayal of Lexi.

Turilli, described in the program as a recent graduate of the Boston Conservatory at Berklee, delivers an impressively poised performance.

Coming across as a performer who understands the power of stillness, Turilli finds the nuance in a character who seems coolly detached but ultimately proves to be anything but.

THE GREAT REVEAL

Play by David Valdes. Directed by Bridget Kathleen O’Leary and Charlotte Snow. Presented by Lyric Stage Company of Boston. Through April 27. Tickets $25-$75. 617-585-5678, lyricstage.com

Don Aucoin can be reached at donald.aucoin@globe.com. Follow him @GlobeAucoin.