[2] Since 1981, the Tibet Autonomous Region government no longer permits new polyandric marriages under family law.
[citation needed] As elucidated further below, the primary reason for polyandrous marriage among Tibetans appears to be economic: to prevent land, herds, and other assets from being divided and/or to increase the amount of labor available to support the family.
The population was further divided into social classes: These wealthier family units hereditarily owned estates leased from their district authority, complete with land titles.
Their primary civil responsibility was to pay taxes (tre-ba and khral-pa means "taxpayer"), and to supply corvée services that included both human and animal labor to their district authority.
To avoid this situation, the solution was a fraternal polyandrous marriage, where the brothers would share a bride.
If the widower remarried another woman, two conjugal families would have been created, leading to the eventual partition of the estate.
Conversely, when a woman with no male offspring was widowed, she would share a husband with her daughter ("bigenerational polygyny"), thus avoiding land partitioning (reference missing).
The householder class (du-jung or dud-chung-ba[5]) comprised peasants who held only small plots of land that were legally and literally "individual" possessions.
If taxpayer sons married that created succession for the family corporation and bound them to the estate for patrimonial and land reasons.
As tre-ba marriages were decided for patrimonial reasons, the brides' and bridegrooms' personal preferences were of no consequence.
Polyandry declined rapidly in the first decade after the establishment of Tibet Autonomous Region, and was banned during the Cultural Revolution as part of the "Four Olds".
[8] Currently, polyandry is present in all Tibetan areas, but particularly common in some rural regions of Tsang and Kham that are faced with extreme living conditions.
[9] A 2008 study of several villages in Xigaze and Qamdo prefectures found that 20-50% of the families were polyandric, with the majority having two husbands.
Representatives of an American charity working in Ganzi Tibetan Autonomous Prefecture, Sichuan Province, from 1997 to 2010 observed polyandry still being practiced there.