It was supposed to be a male, and was looked upon as a result of sodomy.

Rueff says that the procreation of human beings and beasts is brought about-- (1) By the natural appetite; (2) By the provocation of nature by delight; (3) By the attractive virtue of the matrix, which in beasts and women is alike.
Plutarch, in his "Lesser Parallels," says that Aristonymus Ephesius, son of Demonstratus, being tired of women, had carnal knowledge with an ass, which in the process of time brought forth a very beautiful child, who became the maid Onoscelin.

He also speaks of the origin of the maiden Hippona, or as he calls her, Hippo, as being from the connection of a man with a mare.

Aristotle mentions this in his paradoxes, and we know that the patron of horses was Hippona.

In Helvetia was reported the existence of a colt (whose mother had been covered by a bull) that was half horse and half bull.