Today, Christians make up just 1 percent of the mainly Muslim population of the Palestinian territories, said Hanna Eissa, who is in charge of Christian affairs in the Palestinian Authority's religious affairs ministry.
In 1920, they were a tenth of the population of Palestine -- land where today Israel exists alongside the occupied West Bank and the Gaza Strip. The Palestinians remain stateless.
Decades of conflict, shifting borders and occupation are the root causes of the poor economic situation that is forcing Christians to seek better lives abroad, Eissa said.
Rising Muslim fundamentalism, a trend across the Middle East, concerns some. But most cite Israeli occupation as the prime cause of emigration and the decline of their community.
"If there was no political problem, the economic situation would be good, so the problems are linked," Eissa said.
In Bethlehem alone, the Christian population has slumped to 7,500 from 20,000 in 1995. Then, the Middle East peace process had created hope that a Palestinian state would emerge alongside Israel. Some Christians who had left came back.
Sandra al-Shoumali, Abu al-Zulaf's sister, and her husband were among those who invested at the time. They thought peace was imminent and saw a prosperous future in a new state. But talks collapsed in 2000 and several years of violence ensued.
"There was no work, no way to live," she said. "Our family has been scattered," she said. They moved to the United States. She is visiting Beit Sahour for the first time in two years.