When a virus makes everyone over the age of eighteen infertile, would-be parents pay teen girls to conceive and give birth to their children, making teens the most prized members of society. Girls sport fake baby bumps and the school cafeteria stocks folic-acid-infused food.

Sixteen-year-old identical twins Melody and Harmony were separated at birth and have never met until the day Harmony shows up on MelodyÕs doorstep. Up to now, the twins have followed completely opposite paths. Melody has scored an enviable conception contract with a couple called the Jaydens. While they are searching for the perfect partner for Melody to bump with, she is fighting her attraction to her best friend, Zen, who is way too short for the job.

Harmony has spent her whole life in Goodside, a religious community, preparing to be a wife and mother. She believes her calling is to convince Melody that pregging for profit is a sin. But Harmony has secrets of her own that she is running from.

When Melody is finally matched with the world-famous, genetically flawless Jondoe, both girlsÕ lives are changed forever. A case of mistaken identity takes them on a journey neither could have ever imagined, one that makes Melody and Harmony realize they have so much more than just DNA in common.

From New York Times bestselling author Megan McCafferty comes a strikingly original look at friendship, love, and sisterhoodÑin a future that is eerily believable.