Between XX and XY by Gerald N. Callahan is a non-fiction book about sex. It made me realize that I have been unintentionally perpetuating a myth.
Most people know a little about the X and Y chromosomes. If you have two X chromosomes, you are a female. If you have one X and one Y, you are a male. In a perfect world. The reality is that the chromosomes alone don't determine your sex. The chromosomes interact with and are influenced by hormones and other proteins in ways that are not fully understood. And in ways that can go astray, deviating from what we consider "normal." The result: a person with a sex somewhere in between the ideal male and ideal female on the spectrum.
I teach Biology. For simplicity, we go with the ideal situation. XX = female, XY = male.
After reading this book, I will be much more aware of pointing out the shades of gray!