With a shaved head, flowing burgundy robes and religious devotion, Xinde Shijiamouni has all the trappings of a Tibetan Buddhist monk. But her serenity is troubled -- because as a nun, she cannot reach the same clerical status as a man.

In harsh terrain and relative isolation, Tibetan culture has long been patriarchal.

Now more than 100 nuns at the Larung Gar Buddhist Institute -- the largest Tibetan Buddhist academy in the world -- are challenging that, holding study sessions on feminism and sparking a nascent religious movement.

The group have published a series of books on female Buddhist figures and put out a magazine once a year.

But many senior monks view their calls with suspicion, decrying gender equality as a "Western concept".

"If you look at Buddhist law, you can see both genders should be equal," said Xinde Shijiamouni -- whose name is a pseudonym meaning "The Heart of the Buddha".

"But many on the outside don't understand the dharma, and many on the inside choose to ignore it."

More than 10,000 men and women study at the institute, living in red wooden huts that cram into a steep valley at 4,000 metres (13,000 feet) altitude in an ethnically Tibetan part of Sichuan province, besieging the main buildings.

Part of the Nyingma school of Tibetan Buddhism, it was its first college to allow women to achieve a khenmo -- the equivalent of a doctoral degree in divinity.

But the genders lead largely separate existences, with women barred from the academy's monastery, men not allowed to enter the nunnery, and the accommodation all single-sex.

Neither Tibetan Buddhism nor the institute allow women to achieve the same religious status as men, denying them the highest rank of ordination, bhikkhuni, which is held by tens of thousands of monks.

"We should be able to do as well as monks," a senior nun declared at a graduation ceremony at the Larung Gar nunnery last year.

One activist nun, who declined to give her name for fear of reprisals, told AFP: "We're doing this because we nuns have been under attack for so long. We need to teach women to stand up for themselves."

But China's government takes a dim view of religious and political movements not directly under its control -- including women's rights campaigners. An annual meeting of feminist nuns from across Tibetan areas has to be held in secret because it lacks official approval.

- Women's work -

Beijing is deeply opposed to Tibetan nationalism and has been seeking to reduce the number of students at Larung Gar for over a decade. About 2,000 of the distinctive red student huts were demolished in 2001.

Most of the novices are female, but according to researchers the stark gender inequality in Tibetan society contributes to many nuns' choice to take the cloth.

Arranged marriages, domestic abuse and conflict with mothers-in-law all contribute to the decision to become a nun, said Nicola Schneider, of the East Asian Civilisations Research Centre in Paris, who has done extensive field work in Tibetan nunneries.

"Aside from the religious aspect of working for karma and having a better reincarnation, another reason women become nuns that is not very openly talked about is that life as a Tibetan laywoman is hard," she told AFP.

Women do most of the work in rural and pastoral families, who make up more than 90 percent of Tibetans, she added.

As well as their theoretical discussions, the Larung Gar nuns have an outreach programme for laywomen in surrounding areas on female health issues.

"All religions teach compassion and helping others, we're helping women to improve their health," said one nun. "That's not a controversial issue."

Palmo, a professor of Tibetan literature at Northwest University for Nationalities who does outreach work with rural women, believes the nuns will have an impact.

"Change will be slow, it may be a decade or more," she said. "But these nuns can eventually change Buddhist society and possibly even Tibetan society as a whole."

- 'Outsiders interfering' -

Women can hold bhikkhuni status in some countries that follow Buddhism's Mahayana and Theravada traditions, including China, Korea, Vietnam and Sri Lanka.

The Dalai Lama has backed research to address gender inequality, but women are denied it in his Gelug school of Tibetan Buddhism, although the exiled Nobel laureate once told a US award ceremony that he considered himself a "feminist".

"Isn't that what you call someone who fights for women's rights?" he asked.

Older monks at Larung Gar are sceptical of such notions.

"The ideas of 'gender equality' and 'feminism' are entirely foreign," said Wangchuk, a 45-year-old monk walking on the sun-soaked plaza outside the main monastery hall.

"Tibetan Buddhism has generations of history and tradition, we don't need outsiders interfering with that."

But younger lamas are more open.

"It's good for the nuns to study gender equality, the world right now is too unequal," said Pema, 23. "We need more people working to make life fairer."