FORT WORTH — Frontiers is certainly an appropriate title for the Fort Worth Opera’s new-music series. In contrast to the mainstage performances in Bass Hall, Frontiers presents pieces of operas so new they’re not even finished yet.The series is tucked safely away in McDavid Studio across Calhoun Street from the Bass. Judging by Thursday’s and Friday’s sessions, some of the operas would have a tough time crossing the street to the Bass — at least without howls of outrage from the Butterfly crowd. They’re just a little too frontierish.The idea of Frontiers is to give a hearing to works in progress, with performances by young singers in town for the Fort Worth Opera festival and commentary by experienced professionals. From more than 80 submissions, eight works were chosen for this year’s Frontiers.The singers were backed by two pianists and two conductors, taking turns, and performances were without staging or costumes.The subject matter was certainly varied, and in some cases far-out. When’s the last time you saw an opera about a transgendered person’s changeover? Or one about a dominatrix or a robotic servant-lover?The work about gender was Alex in Transition, with words and music by Anthony Green. The opera — or rather, the extract heard Friday — is serious in tone. Mostly it consists of a lengthy lament by a man about the trials of being misgendered, with two brief episodes in which a woman, representing the man’s other self, joins him in humming.The significance of this is not clear, but maybe the work in its entirety would clear up the point. Certainly, the idea of one person singing a duet with himself (or herself) is interesting.Green’s music makes its dramatic points, and I think I detected a change in character and mood depending on which facet of the protagonist’s self was being emphasized.The opera about the dominatrix and the robot (each has its own act) was Three Way, with music by Robert Paterson and text by David Cote. This was a tongue-in-cheek thing good for quite a few laughs, though the no-holds-barred language would raise some gasps from a conventional operatic audience.The idea that the perfect man would be a robot merited a few smiles, and the list of things the customer wanted the dominatrix to do raised the thought: “Are there really people who want that stuff done to them?”Paterson’s score had some nice jazzy measures, but the music tended to pale in contrast to the many yucks.The piece that probably has the best shot at production is Herschel Garfein’s Rosencrantz and Guildenstern Are Dead, which of course is based on Tom Stoppard’s comedy. It got its share of laughs with a clever cast on Thursday evening and had a listenable score, though again the music tended to take a back seat. Fertile Ground, with music by David Vayo and words by Nancy Steele Brokaw, was a winner musically, with a Coplandesque score and a folksy, rather elegiac text.The other works featured were In a Mirror, Darkly, with music by Christopher Weiss and text by S. O’Duinn Magee; Something to Live For, with music and words by Ronnie Reshef; Precari, with music and libretto by Brent Straughan; and Voir Dire, with music by Matthew Peterson and text by Jason Zencka.I felt that Precari has real promise, but the high tessitura of the soprano soloist was tiring, and the segment went on too long.Singers taking part were Kerriann Otaño, Clara Nieman, Ian McEuen, Mat Moeller, Dane Suarez, Meredith Browning, Meaghan Deiter, Cristina Castro, Kevin Newell, Claire Shackleton, Dan Kempson, Steven Eddy, Aaron Sorenson, Corrie Donovan, Megan Garvin and Jesse Enderle.