With the recent "decree" from the US president (January 2025) that there are only two sexes, male and female, I've been lured into looking at more recent articles on the science of sex, sexuality, and gender. Here's the first article which may be of interest:
How Science is Helping Us Understand Gender
"Freed from the binary of boy and girl, gender identity is a shifting landscape. Can science help us navigate?"
From National Geographic:
Many of us learned in high school biology that sex chromosomes determine a baby’s sex, full stop: XX means it’s a girl; XY means it’s a boy. But on occasion, XX and XY don’t tell the whole story.
Today we know that the various elements of what we consider “male” and “female” don’t always line up neatly, with all the XXs—complete with ovaries, vagina, estrogen, female gender identity, and feminine behavior—on one side and all the XYs—testes, penis, testosterone, male gender identity, and masculine behavior—on the other. It’s possible to be XX and mostly male in terms of anatomy, physiology, and psychology, just as it’s possible to be XY and mostly female.
This long and well-written article tells the stories of human beings who don't neatly line up into the "gender binary." You will learn about some of the variations along some of the continua related to sex, sexuality, and gender.
https://education.nationalgeographic.org/resource/how-science-is-helping-us-understand-gender/
Here's a second article about sex, sexuality, gender and sexual orientation:
Sex, Gender, and Sexuality: What the Science Says
"Acceptance of a person’s sexuality and gender identity requires at least some acknowledgment that they are natural and real."
Gender variation among humans has always been the norm. The only thing that has changed is that people are now discussing this reality more openly and honestly. Unfamiliar language and heated rhetoric have confused many members of the public. I’d like to set things straight. (Hogan Sherrow)
...Gender is a uniquely human cultural trait with biological underpinnings that may or may not resemble an individual's sex.
https://www.openmindmag.org/articles/lgbtq-a-guide
Here's a third article, that includes intersex:
Biological sex is not as simple as male or female
"Defining sex as a binary excludes many biological realities, scientists say"
It’s not just about chromosomes. Or reproductive cells. Or any other binary metric. Many genetic, environmental and developmental variations can produce what are thought of as masculine and feminine traits in the same person. And so sex, scientists say, should be viewed in all its complex glory.
“Sex is a multifaceted trait that has some components that are present at birth and some components that developed during puberty, and each of these components shows variation,” says Sam Sharpe, an evolutionary biologist at Kansas State University in Manhattan.
https://www.sciencenews.org/article/biological-sex-male-female-intersex