I recently read The Two Pearls of Wisdom by Alison Goodman (also published as Eon: Dragoneye Reborn and Eon: The Rise of the Dragoneye).
Eon is the main character. He is in training to become a Dragoneye, a powerful lord who is united with one of the twelve mighty dragons of power. Eon is one of many candidates, and due to the fact that he is a cripple, many do not consider him to be worthy of holding the Dragoneye title. But Eon has a dangerous secret. He is not actually a twelve-year old boy… but sixteen-year girl.
Women are forbidden from becoming Dragoneyes- it is said that they do not have the sight. It is a crime punishable of instant death. But Eon has raw power: the power to see all twelve of the dragons. She thinks she has a chance of becoming Dragoneye- until the Rat dragon rejects her. Then, in a unpredictable and fast-moving chain of events, Candidate Eon is suddenly Lord Eon. Thrust into a deadly world of politics, ranks and power, faced by a terrible betrayal by one she loves, and where the entire balance of a nation is held in place by one dying Emperor.