It's all about Polarity.

Look at Genitalia. Males are external (Positive) and Women are internal (Negative)

One gives, one Takes.

Now match the polarity against the Sun and the Earth.

The Sun Gives, the Earth Takes.

Women are of the Earth, Men are of the Sun.

Men are Positive (Spiritual) Women are Earthly (Material)

When Mankind "Fell" (Eve eats fruit, convinces Adam) the polarity became reversed.

Man, who was positive, became negative.
Woman, who was negative, became Positive.

Therefore, in this dispensation, man obtains a return to Polarity Positive by seeking sex (Negative, Earthly Material act) with a Female. (A Man becomes a man again) or mathematically expressed - x - = + While for the Woman it's + x - = -

The Woman becomes negative again in the process.