On a separate, but related topic, I did some research into why some of them are androgenous.
I don't know if this explains it, but what I found was that in classical times, when goddesses were held in high regard, it was not uncommon for men to voluntarily be castrated so they could join the esteemed goddesses in the temples. Maybe that influenced classical art. I'm not sure. I just know that androgeny is common in a lot of classical imagery and a small portion of zodiacs appear to have this characteristic, as well.
Also, for a long time, males played females in theatrical productions (both east and west). I don't know if this had any influence on iconography.
I don't know if this explains it, but what I found was that in classical times, when goddesses were held in high regard, it was not uncommon for men to voluntarily be castrated so they could join the esteemed goddesses in the temples. Maybe that influenced classical art. I'm not sure. I just know that androgeny is common in a lot of classical imagery and a small portion of zodiacs appear to have this characteristic, as well.
Also, for a long time, males played females in theatrical productions (both east and west). I don't know if this had any influence on iconography.