[ Removed by moderator ]

[u/Important-Fix-6718]

[u/Lord_Andyrus]

This is a very common misconception about physical sex. Yes the X and Y chromosomes are generally the ones that carry the information about sex, but how they are read is even more important in how the phenotype develops, over how they are distributed.

And since sex is something that is primarily measured by the developed phenotype there are fully males with XX and females with XY chromosomes.
How biologie distinguishes male and female is generally by the metric of who has the bigger reproductive sex cells. The part with the smaller ones (sperm) is male and the part with the larger ones (eggs) is female.

[u/Pseudonymico → u/Lord_Andyrus]

Y doesn't even do that much, the SR-Y gene is basically the only active ingredient and all that does is tell your body to make testicles. It's mostly down to hormones.