All of that is based on Gender Theory put forth by a guy names John Money. He coined the term gender and his theory is basically that sex and gender are different. He also did some awful awful things (google it if you are curious).
Over the past few years a lot of companies and institutions adopted Gender Theory to pander to those possessed by that ideology and it became almost a norm.
Gender and sex are not different. The sexes are complimentary and, personally, I am against men in women's spaces. You can make up your own mind, just make sure you research the topic well.