The mad scientists of Splice make Victor Frankenstein look like a reasonable man. One of the many perverse pleasures of Splice — an unsettling piece of science-fiction horror in the tradition of director David Cronenberg — is that nothing in the movie is creepier than its two nominal heroes: biochemist couple Clive (Adrien Brody) and Elsa (Sarah Polley), who mix human and animal DNA. Like Cronenberg’s The Fly, Splice uses icky, visceral imagery — gooey stuff you feel you can touch — to explore human psychology, which is far more amorphous. Elsa evades Clive whenever he brings up the notion of their having a baby, yet after their creation is “born” — in a squirmy sequence that’s one part Knocked Up and two parts Alien — Elsa becomes downright maternal. Directed by Vincenzo Natali Splice at times seems to be about motherhood more than the ethics of science. It’s Rosemary’s Baby in scrubs.