Binnaum, also refered to as "the Third ones" are a 3rd Gender of the Tenctonese.
Fertilization of the Female’s egg requires two types of Male. The Binnaum (Catalysator) prepares the Linnaum (Female) for fertilization, the Gannaum (Male) then fertilizes them.
Binnaum children are rare (1 in 100) and do not take permanent mates. Instead, they are expected to grant their services as needed for the continuance of their race. A binnaum is recognizable by the oversized spots on his head. These individuals form a brotherhood and each of them service hundreds of females a year. The ceremony of fertilization is shared by close friends. While holding burning candles, those in attendance discreetly turn their backs on the female as the binnaum prepares her for her spouse. The binnaum prepares the "channel" with the catalyzing emission, and the gannaum (the father) provides the sperm. The binnaum does not contribute genetically to the offspring, however. The ejaculate of Newcomers is referred to as "Aklafluid."
Binnaums, in addition to their role in reproduction, also demonstrate an ability to communicate with others on what has been described in the telemovies as a psychic plane. This communication, not limited to other binnaums, seems to take the form of telepathically transmitted imagery.
The Binnaums are usually organized in the Order of Binnaum, a monastic institution which watches over their Members and assigns them to Females to catalyze them.