Q. I’ve been looking for a book to help explain more about what creates a female versus a male. In other words, I’m beginning to think there’s more to this process than just whether the fetus has a XY chromosome pattern versus a XX. Do you know of any books that are “readable” for a non-scientist?

A. Actually, one of my favorites was written by Melissa Hines, a clinical psychologist who did years of postdoctoral training at the UCLA Brain Research Institute. Entitled Brain Gender and published by Oxford University Press, Inc. (2004), the book contains a wealth of information. Although some of the material is technical and the contents include descriptions of research projects, the language is understandable to a wide variety of readers, including the interested lay person.

More to your question, Dr. Hines wrote in Chapter 5, Gonadal Hormones and Human Sexuality, “Core gender identity and sexual orientation, as well as gender role behaviors, are each independent characteristics and could show different types of relationships to hormones.” She included examples of the multifaceted dimensions of human sexuality and ways in which each may relate to gonadal steroids (hormones) as opposed to chromosomal patterns alone. As a brain-function specialist, I have found Chapter 10 especially fascinating: Sex and the Human Brain. Although similar, the brains of males and females do differ in some structural and functional aspects. Overall intelligence doesn’t appear to be one of them. In other words, although types of intelligences differ among human being in general, and among males and females more specifically, one gender has not been shown to have higher levels of overall intelligence as compared to the opposite gender.

You may be able to pick up a used copy of the book through internet sources such as www.amazon.com.