A promising first novel of domestic and sexual manners whose surface is sleek, swift, and beautifully controlled, but whose center is spongy. The ""boys"" of the title are Adam Berg and Huck Malachowski, ex-freshman roommates at Yale, now nearing 30 and living together again in the almost anything-goes atmosphere of San Franciso in the 1980's. The reason: Adam, a teacher, has fled Boston and a souring love affair for a new job at a posh private S.F. high school, and Huck, who moved West to work as a political consultant when he dropped out of college, is saddled with a nine-month-old baby--whose mother, a mysterious figure, is interned in an insane asylum and appears likely to break out at any moment. After Adam be. comes intensely fond of the baby, Christopher, as well as of a small crowd of minor characters (two gay neighbors who dress as twins; a cabaret singer who makes Adam her sexual slave; a fellow teacher with a fetish for shoes; a bright, obsessive student who introduces Adam to his first gay kiss)--the worst happens: Christopher's mother returns, tries to shanghai the baby, and forces Adam to confront his feelings about his own remote, distinguished mother and make a moral choice in favor of the family and city he has adopted: he lures Christopher's mother into the apartment he shares with Huck and goads her until she knifes him, which sends her back to the loony bin. Adam is not an entirely satisfying character--he's too inexperienced and directtionless to be a convincing ""smart boy"" of 30 or, for that matter, to lead us through a thicket of conflicting values. Still--and even though the plot here is predictable--this is a qualified pleasure to read.