Globally, at least 200 million girls and women alive today have suffered some form of female genital mutilation across 30 countries.
PIC: The United Nations has declared female genital mutilation a human rights violation. (Getty Images)
The widely condemned practice of ceremonial genital mutilation among girls and young women follows an evolutionary logic, according to a provocative study published Monday.
Understanding this logic -- which the researchers described as "cultural", not biological -- may help fulfil the UN goal of eliminated the practice worldwide by 2030, the authors said.
Comparing 47 ethnic groups across five countries in west Africa, they found that in those where female genital cutting was the norm, survival rates were higher among children born to women who had been cut.
The opposite held true for ethnic groups in which mutilation was the exception rather than the rule: women who had not undergone the procedure saw a higher survival rate among their offspring.
The findings, reported in the scientific journal Nature Ecology & Evolution, were based on health surveys covering more than 61,000 girls and women aged 15 to 49.
"Our results indicate that this difference is due to social, not biological, differences," explained lead author Janet Howard, a researcher at the University of Bristol in England.
Women who conformed to the dominant practice in their culture, she told AFP, typically had better marriage opportunities and better access to social networks.
Prevalence of genital manipulation across the nearly four dozen ethnic groups in Mali, Ivory Coast, Nigeria, Burkina Faso and Senegal -- almost 60 percent on average -- varied from less than one percent to more than 99 percent.
In three-fifths of the groups, more than half of women had been cut, the study found.
Howard and colleague Mhairi Gibson undertook the study to look for clues as to why well-funded, high-profile campaigns to halt genital cutting have mostly failed.
"To date, this behaviour has proven resistant to change," Howard said.
"We hope that a greater understanding of why it exists may help inform eradication programmes."
Globally, at least 200 million girls and women alive today have suffered some form of female genital mutilation across 30 countries, according to the United Nations.
While concentrated in Africa, it is also common in some communities in Asia, Arab states and Latin America.
Half of those cut live in three countries: Egypt, Ethiopia and Indonesia, according to the UN.
The practice can include cutting away some or all of the clitoris, as well as the labia minora or majora, often in unhygienic circumstances.
"It irreparably damages girls' bodies, inflicting excruciating pain," UNICEF director Anthony Lake and UN Population Fund director Babatunde Osotimehin said in a joint statement Monday, International Day of Zero Tolerance for female genital mutilation.
"It causes extreme emotional trauma that can last a lifetime," and increases the risk of deadly complications during pregnancy and childbirth, they noted.
The United Nations has declared it a human rights violation.
By looking at the practice in the context of a new discipline called cultural evolution, Howard and Gibson suggest that cutting confers advantages "that may outweigh its costs to physical and psychological health," explained Katherine Wander, a biological anthropologist at Binghamton University in New York state.
"Female genital cutting seems to increase women's reproductive success," she wrote in a commentary, also in Nature Ecology & Evolution.
It is probably disheartening to those working to protect girls to think of cutting as in any way "beneficial", Wander noted.
"Nonetheless, understanding female genital cutting in these terms points to a new target for intervention: the cost-benefit balance."
One hopeful sign, said Howard, is that in most ethnic groups where less than half the women have been cut the practice is declining.
"We predict that shifting the prevalence to below 50 percent" -- what the researchers called a "tipping point" -- "in other groups will have the same effect."