How do women select a contraceptive? Sometimes, the answer's on a map.

Nang Rong is not a place you can easily find on a map. It's one of the poorest districts in Thailand, a flat, remote area 220 miles northeast of Bangkok near the Cambodian border.

The region's soil, poorly suited for intensive agriculture, still supports paddy rice. Most of the villagers are subsistence farmers, growing one crop a year in rain-fed fields. And in the summer, monsoons blow rain and wind in from the Indian Ocean, sometimes washing out whole sections of the district. It's not unusual for the temperature to rise over 100 degrees.

"It's a hot, hot sun," Barbara Entwisle says. continue story