Baphomet is an occult archetype for the Supreme Deity, composed by both the male and female principles. The commonly found art/statue of Baphomet has both a phallus and breasts, representing the interconnectedness between these principles, just like Yin and Yang from Taoism are complementary to each other.

The same duo happens across various belief systems, such as Ancient Egypt (Isis and Osiris, Nun and Nunet), Brazilian Tupi-guarani indigenous people faith (Tupã e Jaci), some esoteric branches of Islam (Alaat or Al-Lat, the female principle of Allah), and so on. And there's also Luciferianism, where there are Lucifer and Lilith sometimes seen as complementary, sometimes seen as "enemies".

Regarding the Christianity, the Holy Ghost is a feminine name in Hebrew, so it'd be the nearest to this female principle of the Supreme Deity, a.k.a. The Mother Goddess (Asherah as others correctly pointed across the comments).

While we tend to see the male-female principles as phallus and vagina, the reproductive organs are actually just a representation on the physical realm from spiritual, energetic polarities. Everyone has both male and female energies (i.e. a man has also female energy within him, a woman has also a male energy within her), and we shall seek to balance them, seeking equilibrium between our inner man and our inner woman.

The patriarchal society tried to erase the figure of the Mother Goddess across the centuries, trying to make us forget how the first belief systems worshipped a Goddess instead of a God (Venus figurines, for example) but it seems like that this knowledge is being rediscovered nowadays.