The Taoist Yin Yang can be thought of as representing the balance of female (yin) and masculine energy. I was surprised to find that the standard male gender symbol on the left is actually the astrological symbol for Mars. (Yes, the standard female symbol is the astrological Venus). Some authorities say that the male symbol is a stylized representation of the god Mars' shield and spear.
I don't think its strictly a religious symbol like the others in my cycle, but I though I should write it up today as Tuesday is named after the Norse god Tyr, but the Romans named it after their war-god Mars: dies Martis.