He is a champion of condoms, a pusher of the Pill, a voice for vasectomies -- and a major reason that the annual rate of Thailand's population growth was cut in half, from 3.2% to 1.6%, in just 15 years. And while he sometimes comes across as an energetic public relations man with a bagful of gimmicks, Mechai Viravaidya, 47, the engineer of Thailand's remarkable drive to curb its birthrate, regards population control as serious business.
In 1974 Mechai, a former government economist, launched a private nonprofit organization, now known as the Population and Community Development Association (P.D.A.), to foster family...