“Egg, meet sperm. Sperm, my mother.” And so it is that 10-year-old Henry James Herman (Jason Spevack) introduces his mother, Patricia (Toni Collette), to Slavkin (Michael Sheen), the college professor whose sperm-bank donation helped create Henry. With the second-highest IQ score in recorded history, Henry is a certified genius whose “Manifesto on the Nature of Truth”—there’s no Santa, no devil, and no God—causes a Catholic-school riot and gets him kicked out for “heresy.” Deploying flashbacks to Patricia’s quirky, death-filled childhood while staging another scene, unaccountably, in Spanish, writer-director Dennis Lee (Fireflies in the Garden) works hard to generate big laughs, but he succeeds best with offhand jokes, like that word, “heresy.” He introduces Slavkin’s people-hating teenage daughter, Audrey (Samantha Weinstein), by having her scream, piercingly, for a really long time. It’s sorta funny but mostly off-putting, as is the one-dimensional surliness of Patricia. Making their screen debuts, young Spevack and Weinstein give the film’s most natural performances and provide its little bit of warmth, but it seems time to petition Collette, a truly gifted actress, to take a long hiatus from playing bitter single moms.