Polyandry is a form of polygamy marriage whereby one woman has more than one husbands. In Tibet those husbands are often brothers (fraternal polyandry). The wife may not say anything on who the father of the child is so as to avoid tensions and in some cases she might be unsure of the biological father. Even though polyandrous marriages are used to curb population growth and minimise land fragmentation, these forms of marriages are not really stable. Usually some of them may be characterised by tensions and clashes between the husbands if there is sexual favouritism and if the younger brother wants to contest the authority of the elder brother.
One of the main factors which give rise to polyandrous marriages is the need to resolve social structural contradictions which would have been created when men and women both inherited family property like land. The brothers would then need to protect the land by maintaining joint ownership of the land meaning that they have to keep their interests undivided. Therefore they resorted to polyandrous marriages because usually the brothers would find their interests divided by their wives' distinct property shares. Therefore, by having a polyandrous marriage, the brothers would be avoiding such type of a problem as there would share a wife.
Tibetans live in the north-western corner of Nepal above 12 000 feet in elevation. According to Ember 281 the Tibetans practice polyandry as a way of adaptation to extreme circumstances. Cultivatable land is scarce because of the mountainous terrain and so most families have less than an acre which is cultivatable. Shortage of cultivatable land is one the factors which give rise to polyandry in Tibet. Most families would want to retain family farms so as to continue to support their families sufficiently. In minimising land fragmentation, the Tibets would minimise the number of women they marry and