While some clans (such as Clan Ghost Bear) promotes long-term "bonding" between pairs of people, others do not. This is because the Clans have few (if any) limitations on how their people co-habit. All Clansmen, regardless of birth, trace their lineage through their mothers, as opposed to their fathers.All Clansmen, regardless of their birth origin, tend to refrain from using contractions.Trueborn generally hold freeborn with disdain however, the Battle of Tukayyid, the annihilation of Clan Smoke Jaguar (Operation Bulldog), the Word of Blake Jihad, and other lesser incidents (such as Clan Wolf-in-Exile's freeborn Khan, Phelan Ward) have fundamentally demonstrated that nurture, rather than nature, has greater impact of an individual's combat performance. Trueborn Clansmen are usually reserved for the military and scientific castes.This process makes most Clansmen " Trueborn" as opposed to " Freeborn" (conception through heterosexual intercourse). Most Clansmen are artificially born in test tubes using genetic material from two donor parents (male and female).For example, the warrior caste are divided into mechwarriors, aerospace pilots, Elemental soldiers, Protomech pilots, and standard infantry. Within each caste, there are further subdivisions.The fifth caste, the "Dark Caste", are considered bandits. Within each Clan, there are several castes: warriors, merchants, laborer and scientist.