SAY YOU'RE A WOMAN, and you have a brother. And one day your brother announces that he's going to have gender reassignment surgery—introducing, well into adulthood, an element of sisterly competition into your relationship. Mary Norris' bracingly honest story "Gender Studies," in a new essay collection about siblings, deals with just such a scenario, and it is remarkable for how bitchy and un-PC and petty Norris allows herself to sound, as she writes of her unease at seeing her brother "come downstairs in the morning wearing a sweater that emphasizes his new little boobs."

Norris' story is one of the highlights of Freud's Blind Spot, a collection organized on the premise that the influence of siblings is one of childhood's most significant. Editor Elisa Albert (author of 2008's great novel The Book of Dahlia) asked 24 writers to contribute thoughts on their own sibling relationships, and a number of funny, worthwhile stories resulted. They're not all winners—Steve Almond's piece is disappointingly formless, and the Q&A format used by one pair of sisters garners banal results—but most are moving and insightful, like Joanna Hershon's "Any Day Now," about a brother with Williams syndrome (a rare condition believed by some to be the "basis for age-old stories about elves).

As with any survey of family experiences, Freud's Blind Spot is endlessly varied—but every essay bolsters Albert's assertion that "siblings, more than parents, more than teachers and friends and lovers and pets, shape the people we are."