Mark St. Germain’s new play, Wednesday’s Child, which has its world premiere starting April 3 on Florida Studio Theatre’s Gompertz stage, tackles issues related to infertility, surrogacy, adoption and other big concerns. But he wants audiences to know that, first and foremost, it’s a murder mystery.

St. Germain, whose previous plays at FST have included The Best of Enemies, Dancing Lessons and Freud’s Last Session, says the idea for the play came out of conversations with artistic director Richard Hopkins about both serious contemporary issues and “forms of plays. We thought an interesting approach would be to do it as a murder mystery.” His tale of a couple unable to have a biological child, the college student surrogate mother they find, and the police detectives drawn into the case when the student ends up murdered “is an entertainment, not a lecture.”

But for St. Germain, writing it was a challenge, as he’s never written a mystery before. “I foolishly thought I could write it as I’ve done other plays,” he says ruefully. “But with a mystery, you’ve got to know where it’s going” and where it’s going to end up.

Fortunately, he’s had help reaching the solution of his puzzle, as FST has staged play readings over the past two years, attended by both staffers with ideas and audience members with questions. “It’s one thing to look at a play in a room, and another when it’s before 50 to 100 people,” St. Germain says. “Once we did that, you could easily tell where people were confused about certain plot points.” So Wednesday’s Child has involved a lot of rewrites. “I’ve had two couples come up to me who had seen two different readings, and they talked about how much it had changed,” St. Germain says. And the version FST theatergoers see onstage this spring may indeed differ slightly in later productions elsewhere, if St. Germain is involved with them.

Within the mystery format, St. Germain says Wednesday’s Child does address broader questions, such as “Why do random things happen?” and “Is what we do worthless?” Added to that, he says, “There’s humor in it.”

Wednesday’s Child, directed by Kate Alexander and featuring returning FST actors Brooke Benson, Rachel Moulton and Alicia Taylor Tomasko and newcomers Susann Fletcher, Duke Lafoon, Heather Michele Lawler and David Smilow, will run through May 24. For tickets and more information, call 366-9000 or visit floridastudiotheatre.org.