Hi!

In many technologically primitive societies it has been noted that a woman's power to bleed without being wounded is a fearful thing to the men. They fear contamination or reduction of their spiritual power, their own relationship with nature, and the society often sets aside a special place for the time of the month usually referred to as a moon hut. It also serves as a place for the birth of a child, and is a place of seclusion protected by myth and social convention. A man may often not eat food prepared by a woman during her period, and she has to be careful not to touch his tools or weapons during this time. (Given the tendency for periods to synchronize in groups of women who live together, the guys must go hungry or go visiting to another village pretty often, huh?). In part because of this mysterious thing happening to women that does not happen to men, I have thought that the second class status often ascribed to women is the result of the male fear of this unknown.
Even in our own society, women on their period are viewed as more unpredictable, less stable, and even flighty, and don't forget the preconceptions of PMS (something my little sis has used to terrify the men of her household for years, yet since I am unimpressed, she has yet to turn that on me!

Not making light of her, because her time of the month has never been easy from the very first, but often she uses her period to vent to them with impunity. They just walk on eggshells around her, and she gets whatever she wants, pretty much.

) I am just saying that even in our own supposedly well educated culture which should be more aware of biological function, a woman's cycle is not well understood by most males, and a measure of that and the half fear associated with it is the crudity of the jokes they make about it.
Some cultures, during childbirth, have the couvade where the hubby has to pretend to parallel the pains and peril of the mother giving birth, and follow a seclusion rule as well. Some anthropologists view this as a support to the new mother during a dangerous time (health wise in particular) while others view the couvade as a male attempt to establish some part in the mysteries of birth and therefore some social control. Control over these mysteries is maintained rather jealously by the women of the group. It has only been in recent times that the husband in our own society has been admitted to the scene of the birth, and this as extended family has broken down and only the nurse or midwife, and sometimes a Dr., along with the components of the primary family unit are present at a birth. A hundred years ago, and even less, the husband was supported by his close kin and friends, usually outside the house around the barn or corral, or later standing around the automobiles as though they were ready to load and run, out of hearing of the birth room in the house, with lots of nervous jokes, imbibing and pacing. Still is in some few areas of the country, I guess.
So, anyway, after all that dance, I would suggest that part of the patriarchal attitude of dominance is based on a long held, primitive fear of women's mysteries and the unknowns of the biological processes.
"It’s not given to anyone to have no regrets; only to decide, through the choices we make, which regrets we’ll have,"
David Weber – In Fury Born