This is the underlying mystery of male and female as we actually find them in this world: the seed comes forth from the male, while it is in the female that its form is steadily delineated and it undergoes its necessary repairs. Two pathways are involved in this, for the female also produces seed, as our rabbis stated: “The woman emits seed of a red color...” (Niddah 31a). This means that the very material (חומר, chomer) itself contains a part that relates to the female, and this is the red-colored component in the body.
However, besides this, the fact is that the male side provides the power governing the overall form. This means that the power governing the overall form of the Likeness of Man exists through the power of the male, while the details of the design are from the side of the female (see Ramban on Leviticus 12:1).