DOHA (Reuters) - Noor was not the first in her Qatari family to marry a close relative, but she may be one of the last.
Throughout the Middle East, Africa and parts of South Asia, marriage between family members has been widely practised for thousands of years, largely as a means of securing relationships between tribes and preserving family wealth, but also as a practical necessity given that genders are often kept separate.
"I wouldn't say that my parents pressured me, but I felt that society expected it," said Noor, who married her first cousin when she was 19. They had a son together but the marriage ended after a year and a half.
"We broke up because of the family dynamics, all the interference. It's not just the couple that's involved, it's the whole family," she said, wearing the traditional black head-and-body-covering abaya and declining to give her family name.
"This society has invisible constraints. They're never mentioned, but you have to follow them."
At least half of all Gulf Arab marriages are between cousins, with at least 35 percent of Qatari marriages between first cousins, according to current research by the Centre for Arab Genomic Studies based in Dubai. In Saudi Arabia, the number ranges from 25 to 42 percent while in the United Arab Emirates, it is between 21 and 28 percent.
At a recent public debate on intermarriage in Doha, much of the discussion focused on the tensions between cultural practices and the science cautioning against consanguineous marriage - defined as marriage between second cousins or closer.
The discussion was part of the "Doha Debates", a series sponsored by the Qatar Foundation and aired internationally that presents four speakers arguing for and against a controversial motion, in this case the idea that the practice of intermarriage should be discouraged.
"I'm living evidence that cousin marriage doesn't work," said Salma, a Sudanese woman living in Qatar who was in the audience and spoke during the question and answer period.
"My parents are both first cousins. My aunt married a first cousin and had two children, both of whom died young. I'm now afraid I'll get diabetes, because everyone in my family has it."
In recent years Gulf countries have introduced mandatory premarital testing for genetic diseases including sickle cell anemia, as well as infectious diseases such as hepatitis and HIV. In Qatar, counseling is required if a potential genetic problem is detected, though the couple are free to marry if they choose.
Public awareness campaigns - particularly one started in Bahrain two decades ago targeting university students in their late teens and early 20s - have been notably successful in reducing rates of genetic diseases such as sickle cell anemia in the country, Ghazi Tadmouri, assistant director of the Arab Centre for Genomic Studies in Dubai, told Reuters.
Yet even Tadmouri, a geneticist, acknowledges that the social advantages of marrying a family member might outweigh the potential genetic disadvantages in some societies.
"It's expensive to marry in the Gulf. Premarital financial negotiations are much easier when done among family members," Tadmouri said. "And it provides a sense of security for the woman. She's not entering into a new world, she's entering a family she knows very well."
Others have expressed concern that testing could lead to social stigmatization.
"Gulf society is a very fragile society. These tests might suggest, 'This girl has a problem, don't touch her'," said Omar, an Omani in his 20s who was in the audience.
When asked in the debate if they were married to or would consider marrying a cousin or other family member, only two out of the more than 300 Qataris, citizens of other Gulf and Middle Eastern countries as well as Westerners of varying ages in the audience raised their hands.
Though not prohibited by Islam, Christianity or Judaism, some cite the hadith, or saying of the Prophet Mohammad, as an injunction against the practice: "Marry those who are unrelated to you, so your children do not become weak."
Others in support of it point out that the Prophet married his own daughter to a first cousin.
"There's a misconception that parents often force their daughters to marry within the family. Our segregated lifestyle often doesn't allow for mixing of the sexes except within the family environment, so many times the only chance of falling in love is within the family, because you are completely closed off from others," Saudi author Samar Fatany told Reuters.
Fatany said that whereas marrying a stranger is often frowned upon, marriage between family members promotes harmony and stability within the family, and encourages a family-focused way of life.
"We're very proud of our extended family lifestyle. It's something we don't want to lose."
With their tiny population of nationals - Qataris comprise only about 250,000 of the country's 1.7 million people - choices of potential spouses, even those who are not relatives, are limited.
"For Gulf Arab nationals, if you don't marry your first cousin, you still are highly likely marry within your clan or tribe. And if you're marrying within your clan or tribe, it's almost certain that you're marrying a relative, which also carries a certain degree of risk," said Alan Bittles, a geneticist at the Centre for Comparative Genomics at Australia's Murdoch University.
"People rely on the family, the clan, for their well-being. (Gulf Arab societies) are tribal societies, and it becomes very political. Particularly if there is a weak central government, clan and tribal affiliations become much more important," Bittles said.
"You've got to weigh the social advantages with the potential genetic disadvantages."
Noor, now 21 and pursuing a degree in international politics at Georgetown University's Doha campus, told Reuters she thought future generations would deal with the issue differently than she did.
"I think we're more modern than that now."
Reporting by Regan Doherty; Editing by Reed Stevenson and Sonya Hepinstall