Kabbalah Library

30) “But if she bears a female child.” Because the left side dominates and the right surrenders to it, everything is two instead of one, and the Nukva, Malchut, is removed from ZA, to attach the Ruach so it clothes in a body. This is so because the left does not sit in the body like the right, for it is more under the force of the Gevurot, since the right, which is male, could mitigate only the judgments of Nukva, which are impure and pure bloods.

But in the female, in which the left prevails, the judgments of the left should be corrected, too, meaning the male judgments. This is why everything is doubled. The impurity is two weeks, corresponding to the male judgments and the female judgments. And also, the days of purity are sixty-six days, thirty-three corresponding to the male judgments and thirty-three corresponding to the female judgments.