"During those days immediately preceding her menstrual period (i.e. the infamously nicknamed 'PMS'), a woman's estrogen level drops to it's lowest point in the monthly cycle. Thus, just before menstruation, women, at least hormonally, more closely resemble men than at any other point in their cycle. Perhaps, then, the only sensible purely biological solution would be to have every corporation, government office, and--especially--military operation run by gay men, whose levels of testosterone would presumably be low enough to offset the hormone's propulsion toward aggression, while they would also be immune to the 'raging hormonal influences' of PMS."
-The Gendered Society, Michael S. Kimmel
p.s. - for those who don't realize it, this means that during PMS, women are hormonally controlled by testosterone. This means that if a woman is "PMS-ing", she is truly just acting like an everyday male (regardless of the time of the month).