Gender-affirming care and gender transition (as the results on Google will call it if you accidentally search "sex transition"), none of this changes your sex,

Gender-affirming care and gender transition (as the results on Google will call it if you accidentally search "sex transition"), none of this changes your sex, most mammals (including humans) have the XY sex determination system, taking estrogens or other hormones doesn't make you lose your Y and gain an extra X, nor does it make you start producing ova, the only difference is how you look and sound, which (hopefully) makes you more comfortable with your gender, and that's why it's called "gender-affirming care" and "gender transition".