Not since [Maureen Daly's] Seventeenth Summer have the agonies and yearnings of sexual avoidance been presented so vividly as in Up in Seth's Room…. [The relationship of Seth and Finn] soon develops into a grotesque battle over whether she is willing to let him—as they used to say in the sex manuals—achieve penetration. She accepts every other form of intimacy with cheerful enthusiasm, but protects her technical virginity with hysterical zeal. This medieval attitude has evidently been absorbed from Finn's parents, who regard her older sister's cohabitation as a terrible tragedy. In the end, Finn and Seth go off into the sunset, after working out a method of satisfaction for him. (It doesn't seem to occur to anybody that she has needs too.) Mazer presents all this with approval and sympathy for the prohibiting parents. (pp. 123, 139)

Patty Campbell, in her review of "Up in Seth's Room...