Singer from the sea - Sheri S. Tepper

An accomplished student and heiress to a great title, Genevieve has been brought up as a Proper Young Lady, carefully instructed in the Covenants -- the inflexible laws governing women of her class. But she must soon take up the time-honoured responsibilities of womanhood: that is to marry a nobleman of her father's choosing and bear a child at the age of thirty.

But Genevieve has another side to her: the girl who remembers all the stories and the secret knowledge learned from her mother, now long dead, the girl who yearns to heed the call of the sea -- though she has never even seen the vast waters that cover most of the surface of her home planet of Haven. And as her fate, to marry the loathsome Prince Delganor, fast approaches, she begins to question the ties that bind her: why noblewomen must wait until thirty to have children, why so many die in childbirth, while peasants thrive into their eighties, and, most of all, why she must wed a man she detests, rather than the commoner she adores.

Genevieve must uncover bitter truths about the seemingly backward planet of Haven, and fight for the rights of womankind, if she is to save her home world from total oblivion.