Biology

"It's a scientific fact that humans come in only two varieties,

and they are: XX for female, and XY for male."

except ...

• You can be born appearing female, but have a 5-alpha reductase deficiency which can cause you to grow a penis at about age 12
• You can be born legally male with an XY chromosome, but if your body is insensitive to androgens, you will appear female
• You can be born legally male, with an XY chromosome, and have a penis and testes - and a uterus and fallopian tubes
• You can be born legally male, with an XY chromosome, but if that chromosome is missing the SRY gene, you'll develop a female body
• You can be born legally female with an XX chromosome, but if one of those Xs has an SRY gene, you'll develop a male body
• You can be born legally female, with an XX chromosome plus a Y chromosome, and you'll develop a male body
• You can be born legally female, with an XX chromosome, but if your adrenal gland doesn't produce enough cortisol, you'll develop a male body
• You can be born with both XX and XY chromosomes - Chimerism - and watch Nancy Grace's head explode

So the next time you think about using biology to cover your ignorance and bigotry, remember that humans come in lots of different models with lots of different options, and maybe you could stop wasting everybody's time trying to smash-fit people into your little "M or F" checkboxes.

hat tip = Dr Janet Dean via FB