A gender symbol is a symbol used to denote the sex of a life form or the gender of a human being.
A common symbol used to represent the female sex is
a circle with a small cross underneath. According to Schott, the most established view is that the male and female symbols "are derived from contractions in Greek script of the Greek names of these planets, namely Thouros (Mars) and Phosphoros (Venus).
These derivations have been traced by Renkama, who illustrated how Greek letters can be transformed into the graphic male and female symbols still recognised today." Thouros was abbreviated by θρ (male,mars) and Phosphoros by Φκ (female,venus) which were contracted into the modern symbols.