>Indian women can be barred from entering the kitchen and handling food, kept away from family members and shunned from offering prayers during what is sheepishly referred to as “that time of the month”.

sounds similar to Judaism and Islam. My pet theory is that in a warm climate with limited access to good hygiene resources (like clean running water) the "separation" practices naturally emerged as something like a way to protect the woman from infection and the others from probably things like blood borne pathogens, etc. (not that ancients knew about infections, pathogens, etc - it is just in the typical way of natural selection the societal groups who didn't practiced the "separation" fared much worse). Of course religion as always hijacked the situation and made it into another tool of oppression.