Inteersex covers a whole lot of different presentations - including some that are recognized as ‘intersex’ but for which no cause is yet known:
https://en.m.wikipedia.org/wiki/Intersex#Prevalence
I’m aware of it tad, as I “suffer” from XYY syndrome.
Which, in my case, means I am taller than my brothers and a tad hirsute. I also have a much higher-than-average testosterone level (which may or may not be caused by XYY). Could have been a bodybuilder without steroids high.
Probably caused me to have a tad of a temper.
Had six kids, 4 daughters and two boys.
MIT engineer and MBA/MS Engineering.
The only reason I even know is I was tested for Tay-Sachs before my wife and I got married, as it runs in her family and mine (no to both of us - recessive gene), although both my wife and mother describe me as “very male”.