In my case I have an SRY gene on my first chromosome, so if I was born XY I would have been born with Swyers Syndrome and definitely therefore intersex although I would have been assigned female at birth.
This is why I am reasonably sure my second chromosome is X, making me XX male. Rare, but we do exist! The SRY gene almost certainly doesn't come from my mother though as if it did she would have had Swyers Syndrome and I am not aware of any Swyers Syndrome people being fertile, so somehow during fertilisation an SRY gene from my father got mixed up during the fertilisation process and genetic recombination.
This is why the idea, much beloved of transphobes such as Dawkins, of biological sex being entirely binary is so very wrong, and also why the howls of "sterilisation" thrown at trans folks is so harmful, as I am a mummy to a daughter with my estranged wife. Hardly sterile then ...