It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize female ova.

In higher animals, ova are produced by female gonads (sexual glands) called ovaries and all of them are present at birth in mammals and mature via oogenesis.

Ridges on the embryonic surface, representing the future genital organs, are present by the end of the fifth week and by six weeks the sexual glands (the gonads) are developing although as yet undifferentiated between male and female.

Bologna and hot dogs (which are almost identical) are catch basins for animal parts that could not otherwise be marketed to humans - like "mechanically separated meat," a pink paste that can include organs, bone marrow and sexual glands.