Birthrates in both simple and advanced agrarian societies have averaged 40 or more births per 1,000 population per year, triple that of most modern industrial societies.  In general, there seems to have been little interest in limiting the size of families, since large families, particularly ones with many sons, were valued for both economic and religious reasons.  From the economic standpoint, children were viewed by peasants as an important asset, a valuable source of cheap labor.  Chilren were also important as the only form of "old-age insurance" available to peasants/  Religion added yet another incentive for large families, either by encouraging ancestor worship, for which perpetuation of the family line was essential, or simply by declaring large families to be a sign of God's favor (1991, p. 172).