LIKE ITS hermaphroditic narrator, Jeffrey Eugenides’ long-awaited second novel is a hybrid–at once a Greek-American family saga and a picaresque coming-of-age narrative.

Unlike the author’s first book, the closely-woven Virgin Suicides, Middlesex is long and episodic, reaching far back across the 20th century and bringing in dozens of characters. While the overall structure is loose, the organization is simple. Calliope Helen Stephanides–now Cal–tells us how he came to be that physiological oddity, possessing both male and female genitalia, how he keeps his secret, and what happens once his true nature is exposed.

This takes some doing. Cal, as our guide to his own life, has chosen to go back two generations to track the unique circumstances that led to the genes responsible for his condition, proposing that, as in Greek tragedy, his fate is preordained. The first 200 pages of the book are dedicated to tracing the family bloodlines–how the Stephanideses left their ransacked Smyrna for Detroit and then made their way in this strange land.

As Eugenides spins their tale of alienation and assimilation, the typical history of the century ticks by–Prohibition, the Depression, World War II. If the progression of time feels schematic, and some episodes overdeveloped, the Stephanideses’ lives are comic and eventful, and lovingly detailed by the narrator.

Eugenides gives Cal free rein, letting him work in first or third person as he chooses, even mixing past and present tenses within the same timeframe. Cal, like the author, is omniscient; he can dip into his grandmother Desdemona’s mind during the torching of Smyrna and then fly offshore to eavesdrop on a conversation aboard a British warship. In his attempt to understand his life, he’s done his research on modern Greek military history, Detroit and hermaphroditism, and isn’t shy about sharing it with the reader.

He’s also alert to anything that mirrors his condition of being two things at once–he’s narrating from the recently reunified Berlin–and piles up metaphors: cocoons and eggs, Ovid’s Metamorphoses, racially segregated Detroit, the partitioning of Cyprus, the seer Tiresias, even a slippery relative who shapeshifts from a bootlegger into the founder of the Nation of Islam. A good many of Eugenides’ choices play into this (the immigrants at once being Greek and American, though no longer fully Greek and never quite American), and while our narrator can and does explain these thematic connections, the constant collecting of them over the course of a 500 page novel becomes relentless.

Middlesex is consistently whimsical in its scene-setting and use of language, but for its subject and all its vaudeville exchanges and niftily isolated punchlines, it’s rarely out-and-out funny. The narration is baldly self-conscious in its cleverness. In the beginning, Cal refers to his brother as Chapter Eleven, and throughout the first half interrupts the story to give us portentous sneak previews of coming events: Only in 1958, when he had stepped from behind the bar of another Zebra Room, would my grandfather have the leisure to remember his youthful dreams of roulette wheels. Then, trying to make up for lost time, he would ruin himself, and finally silence his voice in my life forever. Likewise, and also in the manner of the picaresque, in spots the author takes advantage of his loose structure and has the narrator recap what’s happened so far, as if, in all the commotion, the reader might have forgotten.

For the reader, much of the first half of the book is spent anticipating the birth of its hero, yet when Calliope finally arrives, her early childhood flies by, warranting less than a dozen pages (and begging the question of how her mother wouldn’t discover her secret while changing or bathing her). Following the race riots of 1967, the family flees the city for the suburbs. At this point, after taking so much room to establish a historical sweep across several generations and then skipping her early life, the book noticeably shifts gears once more. The final 200 pages focus on just a couple of years of Calliope’s adolescence, giving Eugenides a chance to revisit the same world of Grosse Pointe he delivered so brilliantly in The Virgin Suicides.

Perhaps this is the author’s true home territory, because it’s here, in Calliope’s sexual awakening, in the tensions of innocent and helpless desire, that Middlesex is at its best. At her private girls’ school, she falls in love with another student Cal can only call The Object, and their teenage romance with all its Nixon-era trappings leads–through a series of improbable events–to her unmasking. The tail-end of the book, covering her testing at the hands of a pop sexpert, her choice to become Cal, and a brief dip into the underworld of porn, is anticlimactic, though the line-by-line writing itself is always jaunty and sharp.

The action stops there, in 1975, except for the containing frame of the novel, the now male Cal in contemporary Berlin. Across the book, he’s been trying to romance a photographer named Julie in the briefest of vignettes, his fear of disclosing his true nature paralyzing him, but the frame is so skimpy, so undeveloped compared to the other sections, that the reader never feels it fully.

And that’s true of Middlesex itself–it’s off proportionally, both section-to-section and overall, its two halves at odds, each interesting at times but neither truly satisfying, despite Eugenides’ prodigious talents. Like Cal, it’s damned by its own abundance, not quite sure what it wants to be.