as much as or more than sequential, short-term partnerships (Hudson, 1993; Morris et al., 1995).
At the same time, however, networks also serve as bases for social support and the development of new behavioral norms. When a person is well integrated into a stable social network, that network becomes a potential resource for behavioral intervention (Morris et al., 1995). Support for behavioral change, such as acceptance of condoms, can enable individuals to negotiate these matters more effectively when confronted with a resistant partner. By the same token, the absence of social networks can make behavioral change more difficult to achieve. For example, young women working in bars may have little social support for developing and negotiating safer sexual practices because they are often migrants from elsewhere and not from the local community.
Several factors lend a special character to conjugal bonds in many sub-Saharan societies: the relatively greater importance placed on lineage and intergenerational links than on marital ties; traditional separation of spousal economic activities and responsibilities; and polygyny (a common feature of married life in many sub-Saharan African populations, although its prevalence varies considerably according to region and ethnic group), which can result in substantial age differences between husbands and later wives (Caldwell et al., 1989; Goldman and Pebley, 1989; Pebley and Mbugua, 1989; Orubuloye et al., 1990). Some men choose to seek extramarital partners as a result of long periods of postpartum abstinence, particularly in West Africa (Orubuloye et al., 1991). Moreover, in certain African societies, premarital sex is an accepted practice, particularly for men. Indeed, a recent study among the Yoruba in Nigeria found that members of either sex who did not engage in such relations could be accused of being timid, sick, or afraid of disease (Orubuloye et al., 1990). 1 Although more women are attending secondary school and fewer are marrying before age 20, the proportion of young women giving birth has remained relatively constant. Because more young mothers are unmarried, premarital births as a percentage of all births to women under age 20 have risen, particularly in Botswana and Kenya, but also to a lesser degree in Uganda and Zimbabwe (Bledsoe and Cohen, 1993).
Across sub-Saharan Africa, a substantial demand for transactional sex outside marriage is met by various types of commercial sex workers. In many cities, particularly those in East and Southern Africa, a core group of prostitutes have multiple clients a week, or in some cases a day. By contrast, in other cities such a pattern is rarer, and commercial sex workers tend to have long-term, albeit sporadic, relationships with a few men over an extended period of time (Caldwell et al., 1989; Karanja, 1987). Consequently, many men surveyed in Ekiti, Nigeria,