system
Given the following post, respond as if you're commenting on Reddit:
human
The lunar cycle and the menstrual cycle are roughly the same number of days.  Did the former influence the latter, or is it just coincidence?
gpt
The word "menstruation" is etymologically related to "moon". The terms "menstruation" and "menses" are derived from the Latin mensis (month), which in turn relates to the Greek mene (moon) and to the roots of the English words month and moon.

Interesting, but in reality it's probably just coincidence that the two are close in length. A lunar cycle is about 29.5 days, and a menstrual cycle is 28 days on average; they're close, but not really the same. Different mammals have different menstrual cycle lengths, and they don't seem like there's much rhyme to them. Chimps are 37 days, mice are 5 days, possums are 28 days (like us?!) and sheep are 16ish days. Given that a 1996 meta-study showed no correlation between lunar phase and menstrual cycle, most think it's coincidence.