Recent fertility trends in less developed countries have led to a decline in family size, mainly due to increased family planning efforts. This decline has significant implications for future world population projections. The amount of effort put into family planning programs is found to be a major factor influencing fertility rates, almost as much as other socioeconomic developments. Between 1968 and 1975, the average family size worldwide decreased by 12%, with 90% of people in less developed nations experiencing a measurable fertility decline. This suggests that future population projections need to consider the impact of family planning programs on fertility rates.