system of incarnate lamas is popularly held to be a Tibetan alteration to Indian Buddhism. Another title unique to Tibetan Buddhism is that of Tertön (treasure discoverer), who are considered capable of revealing or discovering special revelations or texts called Termas (lit. "hidden treasure"). They are also associated with the idea of beyul ("hidden valleys"), which are power places associated with deities and hidden religious treasures. Women in Tibetan Buddhism Women in Tibetan society, though still unequal, tended to have a relatively greater autonomy and power than in surrounding societies. This might be because of the smaller household sizes and low population density in Tibet. Women traditionally took many roles in Tibetan Buddhism, from lay supporters, to monastics, lamas and tantric practitioners. There is evidence for the importance of female practitioners in Indian Tantric Buddhism and pre-modern Tibetan Buddhism. At least one major lineage of tantric teachings, the Shangpa Kagyu, traces itself to Indian female teachers and there have been a series of important female Tibetan teachers, such as Yeshe Tsogyal and Machig Labdrön. It seems that even though it might have been more difficult for women to become serious tantric yoginis, it was still possible for them to find lamas that would teach them high tantric practices. Some Tibetan women become lamas by being born in one of the hereditary lama families such as Mindrolling Jetsün Khandro Rinpoche and Sakya Jetsün Kushok Chimey Luding. There have also been cases of influential female lamas who were also tertöns, such as Sera Khandro, Tare Lhamo and Ayu Khandro. Some of these figures were also tantric consorts (sangyum, kandroma) with male lamas, and thus took part in the sexual practices associated with the highest levels of tantric practice. Nuns While monasticism is practiced there by women, it is much less common (2 percent of the population in the 20th century compared to 12 percent of men). Nuns were also much less respected by Tibetan society than monks and may receive less lay support than male monastics. Traditionally, Tibetan Buddhist nuns were also not "fully ordained" as bhikṣuṇīs (who take the full set of monastic vows in the Vinaya). When Buddhism traveled from India to Tibet, apparently the quorum of bhikṣuṇīs required for bestowing full ordination never reached Tibet. Despite an absence of ordination there, bhikṣuṇīs did travel to Tibet. A notable example was the Sri Lankan nun Candramāla, whose work with Śrījñāna