1. Center for Studies in Demography and Ecology, Department of Sociology, DK-40, University of Washington, Seattle, WA 98195
2. Department of Family Medicine, Chiang Mai Medical School, Chiang Mai 50002, Thailand
3. Thai Red Cross Society, Program on AIDS, 1871 Rama IV Road, Bangkok 10330, Thailand
4. Social Research Institute, Chiang Mai University, Chiang Mai 50002, Thailand
5. Population Index, Princeton University, 21 Prospect Avenue, Princeton, NJ 08544