Sometimes people are born with sexual organs that do not match their genetic make up. I don’t know how it happens, but in some cases they even have both lots of sexual characteristics. Look at the African sportswoman recently who had musles like a man and was tested as a result. They found out she had internal testes and was actually a hermaphrodite.
The fact is that life is a miracle.. if occasionally things go a tad wrong, then that’s just statistics!