The Samaritans of Mount Gerizim were a rapidly dwindling religious community facing extinction. Then a handful of young Ukrainian brides made the journey to the West Bank, bringing with them fresh hope

For decades, it seemed as though one of the world's smallest religious communities was doomed. Dwindling and insular, the Samaritans of Mount Gerizim were struggling to survive as inbreeding produced generation after generation of children with serious disabilities on an isolated hilltop in the biblical landscape of the West Bank.

But the threat of extinction is now receding after the deployment of the twin weapons of advanced medical science and internet marriage agencies to import brides from Ukraine. In fact, the community of four extended families totalling 320 people is now looking forward to rapid growth.

"We're hoping our numbers will reach 10,000 in 10 years," jokes high priest Aharon Ben-Av Chisda, with more optimism than realistic prediction. "Before, we were worried about the future of our community. Now we have hope."

Much of this hope stems from five young Ukrainian women who have injected fresh blood to Mount Gerizim after swapping a life of bleak prospects, dismal housing and badly paid employment for space, security and strict observance of the religious dictates of the ancient Samaritan community.

Alla Altif, 25, the third bride to make the journey from the shores of the Black Sea to the hills of the West Bank, had "no idea what to expect. I was in an uncertain situation, I felt a bit shaky." At first, she says, the isolation was a shock. "But now I prefer it to a big city – it's quiet and peaceful and the air is good." And she and her husband, Uzi, have fulfilled the purpose of their match: they have a healthy son, Morad, who will be two next month.

The women, located by specialist internet-based agencies, have converted from Christianity in order to join the community, whose members are forbidden from marrying non-Samaritans. The brides now adhere to strict biblical traditions, including isolation during menstruation and for long periods following childbirth.

The Samaritans – who share many beliefs and practices with Judaism, as well as marked differences – peaked at around a million during the Roman era. But their numbers fell dramatically as a result of bloody rebellions and forced conversion to Islam. By the early part of the 20th century there were fewer than 150 left.

Alla and Uzi Altif's wedding album. Photograph: Maya Levin for the Guardian

To ensure their survival, they began to produce large numbers of children. But in a shrinking community reluctant to accept converts, inbreeding had catastrophic consequences. Marriage between first cousins was extremely common, leading to a high incidence of serious birth defects and genetic illnesses.

In the 1990s, when the Samaritans at Mount Gerizim were granted Israeli citizenship, they gained access to Israel's hi-tech hospitals, among the most advanced in the world. Routine genetic testing was introduced in the pregnancies of Samaritan women, and abortions were encouraged whenever the risk of birth defects was higher than 10%. Around one in five pregnancies is now terminated, and in the past 15 years, only two disabled children have been born – one as a result of oxygen deprivation during labour, and the other a child whose parents failed to complete the full range of tests during pregnancy. "Genetic testing has vastly improved things," says Ben-Av Chisda, who presides over the Mount Gerizim community and another, 450-strong, in Holon, Israel.

It came too late for the 86-year-old high priest, whose wife is a second cousin. They had four children: three were deaf mutes, and one was unable to walk. The beneficiaries are a younger generation, who include Benyooda Altif, 33, and his first cousin, Mazal, 35, who married seven years ago and have a healthy six-year-old son.

But Mazal's second pregnancy, another boy, was terminated after a blood-clotting problem was discovered. "It felt like I lost someone I knew," says Benyooda. "I had something black in my heart."

The couple are trying for another baby. But, says Mazal, "I'm afraid there'll be something wrong again. The abortion was emotionally very hard."

Her distress was compounded by having to "sit on my own" for 40 days following the termination. The Samaritan religion dictates that women must sleep separately from their husbands, wear special clothes and eat from separate plates for seven days following the start of menstruation, 40 days following the birth of a boy and 80 days after the birth of a girl. Abortion is governed by the same rule as birth.

A Samaritan mother and her childrren make a Passover pilgrimage to their holy mountain last May. Photograph: Maya Levin for the Guardian

This isolation was the one thing that Alla Altif found difficult to adjust to after joining the community in November 2010. "When I have my period, no one can touch me. If I hold my child, then he is unclean, and I have to bathe him before he can touch his father. The separation is hard. Everything else was easy – I just had to learn the rules and follow them."

Her husband, Uzi – who is Mazal's uncle – made contact with her through an agency based in Israel. He visited her home in Kherson, where she worked in a bar, in June 2010. "We met in a cafe, and talked through a translator. We met every day for a week, and then we decided to marry. It was an emotional decision, but I was ready for it. I wasn't afraid – I am a risk-taker by nature," she says.

They married immediately in a civil ceremony. A week later, Uzi returned to Mount Gerizim, and Alla remained in Kherson to complete the paperwork for her emigration. She was already pregnant.

The couple married again, in a religious ceremony. Alla learned Hebrew and some Arabic – members of the community speak both languages – and quickly adapted to being a full-time mother in a large extended family. "I never felt alone here," she says. "These people have open souls. I am surrounded by warmth and love."

Samaritans in the Israeli town of Holon, south of Tel Aviv, have also accepted 15 brides into their community, half from Ukraine and half local Jewish women. Life in the urban sprawl of Israel's most populous area is less of a culture shock than the rolling hills of the northern West Bank, scattered with hardline Israeli settlements and densely populated Palestinian cities and towns.

The children of Mount Gerizim, perched above the Palestinian city of Nablus, attend local Palestinian schools, and are brought up to be bilingual in Arabic and Hebrew. Each member of the community has both an Arabic and a Hebrew name. The community is proud of this: "We don't lean to either side. We are peace-loving people who want to be neutral," says Benyooda.

His brother is now "looking for a Ukrainian girl to marry", he says. Alla has already made one introduction between a Samaritan man and a friend back home, which resulted in a marriage; others may follow. "We are opening our arms to anyone who wants to join our faith," says Ben-Av Chisda. "These women who came didn't come because they fell in love, but because they wanted to become part of our faith. Now they practise our religion even more than our own women."