Woman = female human being
Man = male human being
sex = biological reality of being male or female. or copulation
gender = socially constructed oppression of women based upon sexual stereotypes
sex is a biological reality. it’s how organisms are able to reproduce.
gender is not innate. there is no such thing as ‘brain sex’.
you cannot be ‘born into the wrong body’. similarly, there is no Santa Claus, Easter Bunny or Tooth Fairy.
Also, one cannot >actually< change one’s sex.