James Blish 
Titan’s Daughter 

The tetraploids, giant men and women created by genetic experiment, only wanted to live their lives in peace, but they had to live in the world of the jealous ’normals’ who gathered in screaming mobs with murder in their hearts.Sena, the heroine of this remarkable science fiction novel, is a tetraploid giantess whose youth would last more than a century, who looked with wonder at the toy bridges and houses of normal men and women who regarded her with fear and revulsion. Beautiful, defenceless Sena was the first of a new race, but would she be allowed to live . . . ?