The Principle of Gender manifests that everything has
its masculine and its feminine aspect, with the masculine aspect seen as the 'Will'
i.e. the initiator and the feminine aspect seen as the responder and receiver. The
masculine aspect initiates a creation, the feminine aspect produces it. Neither of
both will get very far without the other.
The gender in this axiom is not to be seen as much as physically male and female but rather like Yin and Yang, as a duality in unity. They are opposing but yet mutually rooted and transformed. They wax and wane, as one aspect becomes smaller the other one fills the remaining space. As in the Principle of Polarity they are opposite poles of the same phenomen.
From the Kybalion:
This Principle embodies the truth that there is gender manifested in everything - the Masculine and Feminine Principles ever at work. This is true not only of the Physical Plane, but of the Mental and even the Spiritual Planes.
On the Physical Plane, the Principle manifests as 'sex', on the higher planes it takes higher forms, but the Principle is ever the same. No creation, physical, mental or spiritual, is possible without this Principle. An understanding of its laws will throw light on many a subject that has perplexed the minds of men. The Principle of Gender works ever in the direction of generation, regeneration, and creation. Everything, and every person, contains the two Elements or Principles, or this great Principle, within it, him or her. Every Male thing has the Female Element also; every Female contains also the Male Principle.
If you would understand the philosophy of Mental and Spiritual Creation, Generation, and Re-generation, you must understand and study this Hermetic Principle. It contains the solution of many mysteries of Life. We caution you that this Principle has no reference to the many base, pernicious and degrading lustful theories, teachings and practices, which are taught under fanciful titles, and which are a prostitution of the great natural principle of Gender. Such base revivals of the ancient infamous forms of Phallicism tend to ruin mind, body and soul, and the Hermetic Philosophy has ever sounded the warning note against these degraded teachings which tend toward lust, licentiousness, and perversion of Nature's principles. If you seek such teachings, you must go elsewhere for them - Hermeticism contains nothing for you along these lines. To the pure, all things are pure; to the base, all things are base.