[EinNYC]

Cued by the rise of certain female hormones, the lining of the uterus (the endometrium) grows thicker at a certain point in the month. This is to form a cushy place for a potential embryo to implant and grow. If the egg for that month is not fertilized, hormonal feedback signals the uterus to shed the thick cushy lining. That is the bloody flow which exits the woman's body through the vagina. So, in order to have a menstrual period, you need to have ovaries and a uterus.

Sorry, boys. No matter how much you may want cramps, the necessity to change your absorptive flow-catching apparatus, or the excuse to be bitchy, you lack the essential anatomy to make it real. If you think you're having a menstrual period, you're not; it's only a wave of perversion running through your head. Just look down; there's your proof that you are not supposed to get menstrual periods.

[SMGFan]

the men who can have periods identify themselves... consider themselves in their mind...as women.

so messed up that we let them identify as something other than biology , but every month they face that hurdle. Those “men” need tampons.