Changing Household Composition, Labor Patterns, and Fertility in a Highland New Guinea Population

Abstract

A multidisciplinary team of researchers have studied the Gainj population in Papua New Guinea's central highlands since the late 1960s. Even though they do not use effective contraception nor practice induced abortion, the total fertility rate (TFR) is very low (4.3). In fact, it is one of the lowest TFRs for a noncontracepting population in the world. Further sexually transmitted diseases are rare thus the Gainj have a low primary sterility rate (1.1%). Moreover premarital pregnancy does not occur. A late median age at 1st birth and long median interbirth intervals contribute to low fertility (25.7 years and 36.5 months). Besides a sizable lag between median age at marriage (21.2 years) and 1st birth exists (4.5 years). In addition, median age at menarche is quite high (18.4 years). Median age at weaning is 38 months. Median lactational anovulation lasts for 20.4 months. These data have inspired the team to determine what effect continuing economic development (Gainj women now grow and market coffee) will have on age at 1st birth, lactational anovulation, and TFR. In 1983, the team surveyed 86 households in 10 Gainj parishes. They consisted of a male head of household and at least 1 wife (conjugal family). It is the cultural and statistical norm and the basic unit of production and consumption among the Gainj. The largest and most significant positive effects on coffee growing success were the number of nonwives, who were the producers, (t=7.4; p