Not a Choice: What you weren’t taught about the biology of sex and gender

Understand the brain differences between women and men, as well as the divergent paths that can be taken on the not-really-binary road to sex and gender identification.

Not a Choice book
Not a Choice

What makes you feel male or female? Or lesbian, gay, binary, or trans? It’s hardwired in your brain. It’s not an either-or coin toss. Certain brain structures develop on a female – male continuum.

With new understanding of the genetics of sex chromosomes, and new discoveries of brain development in the womb, it has become clear that maleness and femaleness are not two separate sides of a single coin. On a spectrum of brain differentiation, full-on female and full-on male are opposite ends that almost no one ever reaches.

Influences of genetics, fetal hormones, drugs, chemicals, and environmental toxins create routes to defining sex and gender that are much more complex than the binary path that we’ve been taught. Internal sex organs, external sexual anatomy, and sexually-differentiated brain structures all are susceptible to these influences at different times during development of the fetus, and therefore may be inconsistent with one another, or internally inconsistent or ambiguous. Inconsistencies between differentiated brain structures and sexual anatomy can cause the feeling of being the right gender in the wrong body.

Gender identity and sexual orientation are set in the biology of specific brain structures during fetal development. Neither is a choice.

Explore the most recent research findings on genetics and male – female brain differences. Pick up your copy of Not A Choice today.


The author puts the topic forward gently, clearly, in a quick-to-read and very interesting package. – Joy Sephton, Editor

This is a nice, clear, short description of the basics of sexual differentiation.
Dick F. Swaab, MD, PhD,
Prof. of Neurobiology, Univ. of Amsterdam
Qiu Shi Professor of Zhejiang University, Hangzhou, P.R. China
Head Laboratory for Neuropsychiatric Disorders
Netherlands Institute for Neuroscience, KNAW

Not a Choice is a layman’s guide to the whys and wherefores of gender, sex, and sexuality written in a language that those who need to know can understand.

A book certain to broaden the reader’s mind, increase our level of understanding of the fluidity of sex and gender, and our ability to accept others (and ourselves) the way we were created and not the way we are expected to be by an uninformed society.

Informative, entertaining, and to the point, Not a Choice is a necessary read for anyone who ever voiced a question about the quirks and differences that make each and every one of us unique and worthy of respect, tolerance, and appreciation. – Eric W. Brown, author On Beyond Yoga

Click on one of the captions below to view on Amazon – Kindle ebook, paperback (black and white interior), and hardcover; or Barnes and Noble – paperback (color interior).

He, She, or They: How do you define “sex”? What they don’t teach you in school

A very short, very quick-and-easy-to-read, high-level view of the influencing factors and timing of sexual development in the fetus. Begins with the fact that some folks have more than two sex chromosomes, and demonstrates the complexity of sexual characteristics. New in June 2022 on Amazon (Kindle ebook).

To read this content in article form, you can find the article here: The Complexity of Defining Someone’s “Sex”.