Global health experts say child marriage - an age-old custom in many nations - is a leading cause of serious health risks for women in the developing world, doubling the likelihood of death during childbirth and leading to lasting reproductive health problems.

Kakenya Ntaiya was engaged to be married when she was five-years-old. Nearly all the girls she knew were married by the time they were 14. Ms. Ntaiya, a member of Kenya's Masai community, decided early that she wanted an education, not a husband.

"I decided that I wanted an education and it was not an easy thing, because I had to actually struggle and go against the traditions that I should get married between age 12 or 14," she said. "That was a big challenge for me to actually convince my father and my community and my elders that I wanted an education."

Eventually, she was able to convince her elders not to force her to marry, but she says it came at a price.

"In my community they do female genital mutilation and I had to go through that and I was age 16 when I had to go through that," said Kakenya Ntaiya. "So I talked to my dad and told him, 'I can only do this if you'll allow me to go to school.' And I told him I didn't want his support financially because I will work on the farm and get my own school fees and things like that."

Ms. Ntaiya related her experience during a discussion sponsored by the non-profit Global Health Council. Now age 25, she has avoided marriage and recently obtained her college degree from a U.S. university in the state of Virginia.

But experts in the field say her story is very uncommon.

According to the International Center for Research on Women, or ICRW, more than half of the girls who live in countries such as India, Nepal, Bangladesh and Uganda will be married before they reach the age of 18. Statistics project that over the next ten years, 100 million girls will be married before age 18.

The head of the ICRW, Geeta Rao Gupta says child marriage is a serious problem with deep cultural and economic roots, especially for women in the developing world.

"Among families who are poor, daughters are viewed as an economic burden or cost that must be shed as early as possible," she said. "And this is because daughters in many societies are viewed primarily as reproducers, as mothers, and as wives, and, therefore, are of value only to the home into which they are married and, therefore, are not of any economic value to their natal home."

She says poverty causes many families to save money by seeking early marriage for their daughters, while they invest in education only for their sons.

Early marriage causes other problems. Young girls who give birth are more susceptible to a condition called obstetric fistula, a hole in the bladder that can occur during a difficult childbirth and that leads to a constant leaking of urine. According to the ICRW, more than two million women around the world suffer from this condition. Many are socially ostracized as a result.

And though many believe that monogamy can safeguard against sexually transmitted disease, the Population Council, a group that conducts research on issues related to women, says early marriage can actually increase the risk of contracting HIV.

Judith Bruce of the Population Council, says that in Kenya and Zambia, girls have a 45 to 65 percent higher rate of HIV infection than unmarried women.

But she says there are some community programs which are having a positive impact. One is under way in an Egyptian village that has a high rate of early marriage.

"Virtually the entire village is participating and supporting girls, who are getting non-formal educations, actually participating in sports, having savings clubs," said Judith Bruce. "And with one of the very important sub-messages being [that] these girls are valuable. They are valuable to themselves, they deserve a chance and early marriage robs them of their childhood."

Ms. Bruce says such programs are most effective when they include parents and elders inside the communities.

Thoraya Ahmed Obaid, the head of the United Nations Population Fund, says governments should pay more attention to the issue of child marriage, and invest more money in trying to prevent it. "Greater action is needed to discourage early marriage and we have to work together to meet the needs and protect the rights of the already married girls," she said.

Health experts agree that cultural norms and cycles of poverty are not easily broken. And experts say both challenges will have to be met in order to decrease the prevalence of childhood marriage.