At plenty of South Florida theaters, the derrieres in the seats belong largely to members of the Greatest Generation or Baby Boomers. Artistic directors know they’re blessed to have these loyal theater lovers at their shows, but another thought fuels their nightmares: Once these folks are gone, will younger theatergoers replace them?

Getting teens and twentysomethings out to a play or musical isn’t easy, not when movies, concerts, clubs and at-home, on-demand entertainment beckon them. Some think live theater is too expensive. Some don’t like the stuffiness of theater’s “rules,” such as arriving on time, not talking or texting during the show, dressing up, not taking photos or shooting video. And some, despite theaters’ marketing efforts, have no idea that there’s a play out there that could make them laugh or cry or get insight into something going on in their lives.

A musical and two plays opening in early November — Girls vs. Boys at the Arsht Center’s Carnival Studio Theater and the world premieres of Antonio Amadeo’s A Man Puts on a Play by The Naked Stage at Barry University and Mark Della Ventura’s roomies at Alliance Theatre Lab in Miami Lakes — are aimed in part at that elusive, coveted audience.

These shows and others help illustrate the ways theaters are reaching out, trying to turn younger people into theater fans.

“You need cheaper prices, sexy advertising and nontraditional media to get them in,” says Girls vs. Boys director J.V. Mercanti. “And we have short attention spans now. … It’s harder to commit to disconnecting for an hour or 90 minutes. We want to be wanted. We want someone to be reaching out to us.”

He adds that a show like Girls vs. Boys, performed by actors not much older than the high school characters they’re playing, can absolutely disprove the notion that theater is a stodgy, uptight art form.

“This is a very typical teen experience and also an extreme version of it, with drinking, sex, abortion, pursuing sex in order to make your relationship work or make yourself feel better,” Mercanti says. “The students bring a level of understanding to it that older actors, looking back with nostalgia or bitterness or a specific point of view, just wouldn’t.”

Girls vs. Boys, previewing Thursday and opening Friday at the Arsht, is the second joint effort by the performing arts center and the University of Miami’s Department of Theatre Arts. A musical with a score that mixes rock, pop and electronica, the piece was born at Chicago’s House Theatre, where collaborators Chris Mathews, Jake Minton, Nathan Allen and composer Kevin O’Donnell presented their show about sexed-up, angsty high school kids after a 2009 debut at Northwestern University’s American Music Theatre Project.

Arsht executive vice-president Scott Shiller suggested the musical to Henry Fonte, UM’s theater chairman, for their next joint project, after last season’s The House of Bernarda Alba. Allen and his Girls vs. Boys co-creators welcomed the chance to revisit the show, reworking it in person and via Skype sessions.

Getting younger people to connect with theater isn’t so tough, Allen says.

“The No. 1 thing is just content. We get asked all the time, ‘How do you get these young kids?’ We’re not producing shows about 19th century aristocracy. You sucker them in with a flying cheerleader [as in The Sparrow], then you can hook them. We’re mindful of ways you can welcome them into the theater,” he says.