It turns out that Andrea Riseborough had an almost psychic connection with Brandon Cronenberg when reading the screenplay, or at least caught on to the way he may have hinted at the idea in the updated script. Cronenberg recalled the moment the actress suggested that her character should, indeed, don a penis for the scene:
“I sat down with Andrea for one of the first conversations we had once she had already signed on to the film, and one of the first things she said when we were talking about the sex scene, was, ‘Look, I don’t want to freak you out here. But I really think that Vos should have a penis.’ I just thought, ‘This is amazing. You’re reading my mind. You’re clearly the perfect person for this.’ And I was just thrilled to go back to my producers and say, ‘She absolutely must have a penis. This is her idea.'”
Riseborough wisely caught on to the fact that Cronenberg’s intention for the scene wasn’t to shock for the sake of exploitation. There’s a deeper theme here about the blending of sex and gender since both characters are part of the same body. The moment makes the audience question where the identity of both characters begins and ends, or if they’re one and the same. In their fight for control, perhaps they’re turning into each other and becoming the same being. Just because there’s a penis doesn’t mean it’s, as Cronenberg succinctly puts it, “penis-focused.”
