Evolution’s rainbow: diversity, gender, and sexuality in nature and people

by Joan Roughgarden.
Berkeley: University of California Press, c.2004.

In this book, the author challenges accepted wisdom about gender identity and sexual orientation.  She takes on the medical establishment, the Bible, social science – even Darwin himself. She leads the reader through a… discussion of diversity in gender and sexuality among fish, reptiles, amphibians, birds, and mammals, including primates.