Robert Zeigler is an environmentalist, but he is also a plant scientist. And that has led him to question the motives of an environmental movement that opposes genetically modified crops despite overwhelming evidence that they are safe.

As director general of the International Rice Research Institute, Mr. Zeigler is pushing the development of "golden rice," a genetically modified variety that began in the lab about two decades ago. Geneticists inserted a gene into the rice plant that allows it to produce beta carotene, which makes its grains yellow.

Because the human body converts beta carotene to vitamin A, golden rice has the potential to dramatically improve the lives of millions of people around the world, particularly in Africa and Southeast Asia, where vitamin A deficiency is an especially common malady that can cause blindness and increases the risk of death from disease. Children are particularly vulnerable: "An estimated 250,000 to 500,000 vitamin A-deficient children become blind every year, half of them dying within 12 months of losing their sight," according to the U.N. World Health Organization.

Golden rice thus sounds like a godsend--but don't tell that to activists opposed to anything that falls in the category of genetically modified organisms, or GMOs. [...]

More than just golden rice is at stake. Total rice production is stagnant but populations are growing. Asia badly needs a second "green revolution" of increased yields--Mr. Zeigler estimates that the harvest must increase to 550,000 tons of milled rice a year by 2035 from 450,000 tons today.

One important way to achieve that is through genetic modifications that will produce higher-yielding varieties, and the International Rice Research Institute will be central to that effort. Founded in 1960 with funding from governments and the Ford and Rockefeller foundations, the IRRI was one of the leading institutions in the original green revolution of the '60s and '70s. Transgenic technology is becoming an important part of its research arsenal.