Menstruation Is Exclusive to Female Reproductive Physiology

Menstruation is the cyclic shedding of the uterine endometrium in response to progesterone withdrawal after an ovulatory cycle without implantation. It requires:

• Uterus with functional endometrium.
• Ovarian follicular development and corpus luteum formation.
• Hypothalamic-pituitary-ovarian axis.

Males lack these structures and hormonal milieu. Transgender men (assigned female at birth) who retain a uterus may menstruate unless suppressed by testosterone therapy. Cisgender men do not and cannot menstruate.