Gender is not the same as sex - In the VO2 max section. My VO2 max is in the top 15% of people my sex (ie with XX chromosomes). It will be much lower compared to anyone with XY chromosomes, regardless of how anyone identifies their gender. Also there are other types of IUD available (such as copper)that are not hormonal - in the menstrual cycle section. Copper IUD’s will generally make periods heavier - great info for a period tracking app to have.