Medicine recognizes two types of androgynous. A true androgynous has both male and female sexual glands, while a Pseudohermaphrodite has the appearance of both male and female sexual organs, although the individual actually has only one set of sexual glands.
Generally speaking, there is a requirement that the animal be a certain age and sex in order to be sanctified as a specific sacrifice to be brought on the altar. It is therefore hardly surprising that animals whose sex cannot be determined cannot be brought as sacrifices, as is taught on today’s daf (=page) by Rabbi Eliezer.
Rabbi Eliezer offers a list of animals that can neither “become holy nor can cause holiness,” and included in the list are animals found to be either a tumtum or an androgynous. Each of these conditions refers to a situation where the animal’s sexual identification is questionable. An androgynous appears to have both male and female sexual organs, while a tumtum does not appear to have any external sexual organs that would identify it as either male or female.
According to the Gemara in Massekhet Yevamot (daf 83) there is some question about how to approach animals with these conditions. Rabbi Yossi suggests that an androgynous is a beryah bifnei atzmah – a unique creature who cannot be treated either as male or as female. The rishonim have different approaches to the definition of beryah bifnei atzmah. Tosafot understand the concept as a permanent situation of safek, of doubt, suggesting that since we cannot expect to ever ascertain whether the individual is male or female we refer to such a person as a unique creature. The Ramban, on the other hand, accepts the simple meaning of the expression, and rules that an androgynous is truly viewed by the halakhah as a creature that is neither male nor female.