With YA novels gaining crossover appeal in the adult market, in many cases the dividing line between the two genres can be ambiguous. Three prominent YA writers — Melissa de la Cruz (the Blue Bloods series); Ellen Hopkins (Fallout); and Melissa Marr (The Wicked Lovely series) — who have all recently penned adult novels, gathered for a panel during BEA for a lively conversation about the experience of writing for older readers.

Moderator Cathy Berner, children’s specialist at the Blue Willow Bookshop in Houston, began the discussion by asking the authors why they chose to venture into adult fiction. Marr, whose Graveminder (William Morrow, May) centers around a small town where the dead associate with the living, responded by saying that she didn’t set out to write a book for adults, necessarily. “I wrote the story that I wanted to write.”

Cruz’s adult debut, Witches of East End (Hyperion, June) surrounds a family of witches in a fictionalized area of the Hamptons. She initially thought of writing for adults because she has so many adult fans already. She also liked the idea of trying something new and different: “I wrote all of the sex scenes first,” she joked, explaining that writing for adults was liberating in some ways.

Because her novels-in-verse deal with edgy subject matter, Hopkins and her editor reasoned that writing for an adult audience might be a natural transition. Her adult novel, Triangles (Atria, Oct.) centers on two sisters and a friend who experience “midlife meltdowns,” and reevaluate the directions that their lives are taking.

The authors discussed some of the differences between writing for teens verses writing for adults. “I swear more in YA,” said Marr, without hesitation. “My adult books are cleaner,” which got a laugh out of the audience. She then explained that in Graveminder, she used a writing style that would be more consistent with her characters and the mysterious atmosphere that they inhabit. Regardless of whether a book is intended for an adult or teen audience, Marr suggested, an essential question to ask is: “What is the protagonist’s journey?” She also said that she doesn’t normally write a YA novel in chronological order, but did so with Graveminder, possibly because the novel—a mystery—needed to unfold in a certain way.

“Everything is more elevated in adult,” Cruz commented. She also said she’d had more difficulty “pinpointing the story” behind Witches of East End than she normally has when writing her YA novels.

The panelists agreed that adult characters may have different priorities and interiority than do teen characters, particularly because adults have already formed their personal identities; teens are still struggling to form theirs. “Being an adult comes with a whole new set of issues,” said Cruz.

Hopkins, who traditionally writes in free verse, said she varied the narrative structure of Triangles by incorporating a poem with an omniscient voice to break up the individual voices of her adult protagonists.

Berner then broached the subject of whether teen readers will or should read their adult novels. Marr mentioned that many of her books do have crossover appeal for adult audiences, particularly among romance readers; she believes that her teenaged readers will decide for themselves (and maybe with their parents’ input) whether or not to read Graveminder.

Hopkins who admits having read “verrry inappropriate books” when she was a teen, and is often outspoken about freedom of expression, responded: “I remind readers that this is the adult book... but you might want to read it anyway.” She also commented that she may worry about some of her younger fans reading Triangles: “It is an older book.”

The authors agreed that there is often a continuum of themes, ideas, and even characters between their YA and adult books. Characters from Cruz’s Blue Blood books actually appear in Witches of East End, which will likely draw her YA fan-base and Marr’s Graveminder has a teenaged girl character. Hopkins felt so strongly that the teenaged supporting characters in Triangles had their own stories to tell that she is writing a YA companion book about them, which will appear in 2012.

All three authors said they look to their personal interests and experiences in writing their adult titles, as they would for writing YA. When writing Graveminder, Marr was inspired by Irish folklore about tending to the needs of the dead to prevent their return to the land of the living. Cruz mined Norse mythology, adding, “I wanted to write about a family of women.” Hopkins didn’t look too far from home, basing the characters in Triangles on her friends, to whom she promised galleys after the show. (“Good luck, Ellen,” Berner teased).

What’s next for Marr, Cruz, and Hopkins? All three plan to continue writing predominately YA, but say they will also work on books for adults. Cruz is working on the next Witches of East End book as well as a sixth Blue Blood book and a Blue Blood spin-off. Marr is writing a sequel to Graveminder and a new YA series, titled Carnival of Souls, debuts in 2012. In addition to her YA companion to Triangles, and a sequel to the YA bestseller Burned, Hopkins is planning an adult work about those left behind when service men and women are deployed.

In the end, the authors concluded that while adult fiction and YA fiction may have different ingredients, the impetus for telling a particular story comes from the same place. Marr elaborated by suggesting that each book has to be told in its own way: “It’s not how do I write a book... It’s how do I write this book?”

Berner ended the discussion by saying how exciting it is for the authors to be branching off into adult territory, but added, “We’re thrilled that you’re staying in the YA realm.”