PIP: At current growth rates, world population will double from 5 billion in 1987 to 10 billion by 2030. This doubling time is extremely short compared to the 1700 years spanned over which world population doubled to 600 million from its 1 A.D. size of 300 million. The rate of population growth has fallen since its 1970 peak, but the momentum of growth and the absolute increase in population numbers remain of staggering population. Two recently improved sets of cross-country panel data from Summers and Heston, and UN World Population Prospects are combined in a re-examination of the effects of population growth and fertility on economic growth. A 107-country panel data set is employed for 1960-1985. Review indicates that high birth rates appear to reduce economic growth through investment effects and possibly capital dilution, but classic resource dilution was not observed. Birth rate declines have a strong medium-term positive impact on per capita income growth through labor supply or dependency effects.