Serious comedy, powered by an enthusiastic cast and full of good-natured innuendo, Lisa Cholodenko’s Kids gives adolescent coming-of-age and the battle of the sexes a unique twist, in part by creating a romantic triangle among a longstanding, devoutly bourgeois lesbian couple Nic and Jules (Annette Bening and Julianne Moore) and the newly identified, merrily free-spirited sperm donor, Paul (Mark Ruffalo), responsible for both the couple’s teenage children. Normality, as made clear by the introductory family dinner that features two mothers acting all motherly, rules. (The moms’ designated kink is their occasional use of gay male porn as an aphrodisiac.) Whereas Cholodenko’s two previous features, High Art (1998) and Laurel Canyon (2003), each focused on an innocent young woman swept up in the glamorously baffling sex-and-drugs scene swirling around a charismatic older female artist, the situation here is reversed; unexpectedly drawn into and fascinated by the ultra-domestic household created by a pair of charismatic femmes, the swinger is the straight man (literally). Premiered last January at Sundance, Kids triggered a lively bidding war. The enthusiasm is unsurprising: It’s actually a pretty conservative movie. Given its juicy premise, Kids could have been played for sitcom, reality show, or soap opera; had it had been made in 1970, it might have been an Echo Park Teorema, with everyone winding up in bed together. Ten years into the 21st century, it’s a heartfelt poster for family values.