XX is XX and XY is XY no matter what you want to look like on the outside.
It's not so simple.
From another thread....
Not that it will help; homophobes are a resistant lot, but ... I happened upon a "United Humanists's Post" that I believe worthy of reposting: Rebecca Helm, a biologist and an assistant professor at the University of North Carolina, Asheville US writes: “Friendly neighborhood biologist here...
www.religiousforums.com
Excerpted...
If you know a bit about biology you will probably say that biological sex is caused by chromosomes, XX and you’re female, XY and you’re male. This is “chromosomal sex” but is it “biological sex”? Well...
Turns out there is only ONE GENE on the Y chromosome that really matters to sex. It’s called the SRY gene. During human embryonic development the SRY protein turns on male-associated genes. Having an SRY gene makes you “genetically male”. But is this “biological sex”?
Sometimes that SRY gene pops off the Y chromosome and over to an X chromosome. Surprise! So now you’ve got an X with an SRY and a Y without an SRY. What does this mean?
A Y with no SRY means physically you’re female, chromosomally you’re male (XY) and genetically you’re female (no SRY). An X with an SRY means you’re physically male, chromsomally female (XX) and genetically male (SRY). But biological sex is simple! There must be another answer...
Sex-related genes ultimately turn on hormones in specifics areas on the body, and reception of those hormones by cells throughout the body. Is this the root of “biological sex”??
“Hormonal male” means you produce ‘normal’ levels of male-associated hormones. Except some percentage of females will have higher levels of ‘male’ hormones than some percentage of males. Ditto ditto ‘female’ hormones. And...
...if you’re developing, your body may not produce enough hormones for your genetic sex. Leading you to be genetically male or female, chromosomally male or female, hormonally non-binary, and physically non-binary. Well, except cells have something to say about this...
Maybe cells are the answer to “biological sex”?? Right?? Cells have receptors that “hear” the signal from sex hormones. But sometimes those receptors don’t work. Like a mobile phone that’s on “do not disturb’. Call and cell, they will not answer.
What does this all mean?
It means you may be genetically male or female, chromosomally male or female, hormonally male/female/non-binary, with cells that may or may not hear the male/female/non-binary call, and all this leading to a body that can be male/non-binary/female.