Robert Moses is known for his sinuous, rapid-fire choreography and his dancers are known for their enviable ability to slide gracefully through movement so complex that the average audience member eye-brain connection is speed dazzled. The performance this weekend marks the world premiere of a behemoth of a project. The Cinderella Principle explores non-traditional family groupings (two dads, two moms, older parents, in vitro and all the waiting and wondering and hoping that entails) culled from interviews conducted with twelve Bay Area families and arranged by award-winning playwright Anne Galjour. Set to live music (violin by Todd Reynolds and beatboxing by Kid Beyond), the text is juxtaposed against the movement - dancers step gingerly on each other's shoulders crossing the stage on a human bridge, tiny infant overalls plummet from the sky, wire hangers are twisted into poignant representations of not-yet-arrived babies. The Cinderella Principle is a graceful and symbolic ode to the desire for children and the difficulties that desire can present.

February 25-27 at Yerba Buena Center for the Arts, 701 Mission Street. Tickets are $20-35 at (415) 978-2787 or www.ybca.org.