I’ve been thinking recently about cross-gender casting. It came up again last weekend in Cymbeline at Shakespeare & Company, where 17 of the play’s 23 male roles were played by women. This was more a matter of necessity than an artistic choice. The show was the culmination of this year’s conservatory program, where women outnumber the men almost three to one.

Shakespeare, of course, is notoriously male-heavy, but even in the contemporary repertoire women’s roles remain a distinct minority. The comparatively recent growth of nontraditional casting—which has also benefitted actors of color—springs in part from an affirmative-action impulse on behalf of an underrepresented cadre of performers. In the case of women, it also responds to the sheer pressure of numbers. Most training programs are majority female (this year’s student body at PVPA, the Valley’s performing arts public school, has twice as many girls as boys) and community and professional theaters alike generally see more women than men at auditions.

Theaters are increasingly adopting gender-blind casting for non-gender-specific supporting roles—servants, shopkeepers and the like. But some directors are casting women in specifically male roles to make an artistic—or political—point. Toby Bercovici’s 2006 production of Ibsen’s A Doll House at Smith College had an all-woman cast, in part to underline, as she says, “the gendered violence of the piece, as the female actors demonstrated& male dominance without actually embodying it.” Last summer Hampshire Shakespeare Company’s Taming of the Shrew gender-switched the entire cast to make much the same point.

I’ve been thinking about this issue as a director, too. For last month’s production of Gilbert and Sullivan’s The Sorcerer with the Valley Light Opera, I cross-cast the title role to balance the script’s power relationships—and because it was high time a woman got to play one of G&S’ flamboyant “patter-song” parts. For Brecht’s Mother Courage at PVPA next spring, I’m creating a six-woman ensemble to play the 20-odd supporting roles, most of which are men. This move was born of necessity—30 girls and nine boys auditioned—but it also supports an implied theme in the play: that wars are waged primarily by men, but women are disproportionately swept up in the onslaught.

Not surprisingly, cross-gender casting doesn’t often go the other way—putting men in roles written for women—in part, I suppose, to avoid “reverse discrimination” on an already tilted field. Recent exceptions include Williamstown Theatre Festival’s 2010 version of A Funny Thing Happened on the Way to the Forum with an all-male cast, reflecting its source in the Roman theater of Plautus.

In Shakespeare’s day, too, all the parts were played by men and boys—which is one reason why there are so few women in his plays. His audience accepted that convention, just as they willingly believed that two unrelated actors were identical twins or that a girl dressed as a boy can fool everyone who sees her. “The willing suspension of disbelief” that allows us to enter a world made of greasepaint and plywood and flesh it out with our imaginations is part of what makes theater unique and magical. Seeing more women on the stage not only promotes parity in the profession; it invites us to engage our mind’s eye more fully, and can even offer up unexpected insights into the cross-currents of human relationship.

Chris Rohmann can be reached at StageStruck@crocker.com.