I keep trying to get my head round the fuzzy language from Bloody Good Period, The Vagina Museum et al about things female bodies do and have. So I read this article, which didn't help me understand, gave me a bit of a headache - but, the comments are worth a read.
www.menstrual-matters.com/blog/maths-people/?fbclid=IwAR3gghJebX4tFViA2NmsMeIDcdyf4zfYwW0ATiWP9FUJ7iRPBA-yGJqnJ1I