Rising standards of living in Third World countries could lead to enormous world population growth unless family planning programs receive strong support, Harvard population experts said yesterday at a symposium sponsored by the School of Public Health.

Since better nutrition generally leads to increased fertility and the death rate in developing countries usually drops more rapidly than the birth rate, these countries undergo rapid population growth, said panel members at "Population Change in Today's World," moderated by Gamble Professor of Population Sciences David E. Bell.

Better nourished women generally become fertile earlier, reach menopause at an older age and become fertile again more quickly after pregnancy, according to Associate Professor of Population Studies Rose E. Frisch. As a result these women can give birth to more children.

"So as women get better nourished, they must be protected from their increased fertility," Frisch said. "We may need much more family planning than is currently being funded."

Associate Professor of Demographics Joseph E. Potter did offer some hope for population control, predicting that the world population will settle at 11 billion in the year 2170.

However Potter said "Demographer's predictions should be taken with a grain of salt. In my opinion they include a certain amount of wishful thinking."