This question is usually asked in bad faith, but I'll bite.
Gender ideologues or genderists believe that whether someone is a man or a woman is determined primarily by that person's gender self-identification ("A woman is anyone who identifies as a woman").
This in contrast with the classic belief, held by radical feminists, J. K. Rowling, and many others, that whether someone is a man or a woman is determined primarily by the physical attributes of their bodies related to biological sex (genetics, hormones, gonads, etc.)
This question is usually asked in bad faith, but I'll bite.
Gender ideologues or genderists believe that whether someone is a man or a woman is determined primarily by that person's gender self-identification ("A woman is anyone who identifies as a woman").
This in contrast with the classic belief, held by radical feminists, J. K. Rowling, and many others, that whether someone is a man or a woman is determined primarily by the physical attributes of their bodies related to biological sex (genetics, hormones, gonads, etc.)