This is all getting seriously out of hand. Partly because people don't get the difference between sex and gender. Your sex is what you are born as, not assigned as some people like to say, but observed. I used to work as a Midwife and I can assure everybody that we didn't go around saying that today all the babies born between 9 am and 3 pm will be assigned as male, and between 3 and 9 we'll assign them as female. Sex is what you are, depending upon your genetic makeup. I won't go into the intersex argument, this is not what happens normally.
Gender is what society deems to be the proper 'way of being' depending upon whether you are male or female. Just a societal construct in fact. And hereby lies a problem. Just because you are a male child, but just happen to like dolls and prams (as my son did for a while), and indeed princess dresses, does not mean you are a girl. Or, if you are a girl and are a little grub in overalls and wellingtons digging in the mud with your dad (as my grand-daughter did for a while as a child), does not mean you must be a girl in my son's case, and boy in my grand-daughter's case. If their parents had been concerned that either of them might, oh dear, be 'gay', then how much better is it to encourage them into the opposite sex, which they are not and can never be. And indeed both of them grew up into normal male and female adults.
Male to female transgender people, who are taking female hormones in order to transition, may get pre menstrual symptoms from said hormones, but they cannot, absolutely cannot have a period, which by definition is the breakdown of the uterine lining after it is no longer needed for an implanted embryo. Males whether transitioning or not, do not have uteri, and so far as I can remember do not ever have implanted, or non implanted embryos.
As for being called out as 'transphobic' for stating biological facts, then I really think we are in danger of collectively losing our minds.