st of replacing it with powder substitutes. The GIFA study points out that the decline of breastfeeding costs the world billions of dollars in increased health care costs for the treatment of babies who fall ill from bottle-feeding.24 Various studies have established that the poorer the socio-economic and environmental conditions under which families live, the greater the difference in health between breast-fed and bottle-fed infants. One study in Ghana suggested that the national cost of rehabilitating all children who were malnourished due to artificial feeding at low-cost nutrition centres would have been between US $100,000 and $800,000 back in 1976.25 This figure does not include any costs to the child's family, any illnesses other than malnutrition, or any capital costs for constructing nutrition centres, all of which would dramatically increase the estimate. The economic value of the natural contraceptive effect of breastfeeding is also difficult to calculate but likely to be significant, particularly for the benefits to women's health which birth-spacing promotes.26
The second method attempts to calculate the 'opportunity cost' of women's housework, that is the money that women forgo by working at home rather than in the formal labour force. To return to a breastfeeding example, a study in the late 1970s compared the opportunity costs of breastfeeding and bottle-feeding infants in Ghana over a two year period. The researchers estimated that breastfeeding and related activities (including some education, preparing and eating extra food for the mother) took 50 minutes daily, while bottle-feeding and related activities (including education, preparing formula, cleaning utensils, and purchasing or collecting extra water and fuel) took 180 minutes per day. The monetary value of time spent was determined to be the average wage for all women, which resulted in an opportunity cost over two years of US $210 for breastfeeding and $600 for bottle-feeding.27 When the opportunity cost of bottle-feeding is combined with the actual costs of replacing breast-milk with substitutes, it could easily be overwhelming for many families whether large or small. Yet Eve's contribution to the economy, through the milk she produces from her own flesh, is ignored and even pushed out of sight.
Neither of these methods is completely satisfactory, however.. With regard to replacement cost estimates, the personalized services provided by a wife and mother would be difficult to purchase on the market. Furthermore, as the breastfeeding example shows clearly, there are many intangible and non-quantifiable aspects to the goods and services provided by women. At the same time, the 'opportunity cost' estimates are also unrealistic. They depend on the labour force being expandable to accommodate all women who are now housewives, and on these women having skills which are needed by the labour force. There are obvious problems with both assumptions. Furthermore, the opportunity cost would be calculated based on already deflated wages, given that women are often confined to low status and low paying jobs regardless of their personal potential.28 And since most rural women in Africa are engaged in subsistence agricultural production rather than, or in addition to, wage employment, determining the opportunity cost of their time becomes even more complex.
Women's roles in agriculture are often overlooked as productive activity, unless they work for wages. Women constitute on average approximately 50 per cent of the agricultural labour force in Sub-Saharan Africa, 30 per cent in North Africa and the Middle East, 40 per cent in South Asia, 54 per cent in South-East Asia, 40 per cent in the Caribbean and 18 per cent in Latin America.29 It was Esther Boserup's influential study in 1970 entitled Women's Role in Economic Development which first brought the role of African women in agriculture to the eyes of the world as a whole. Boserup classified much traditional African agriculture as female-oriented due to its shifting nature and hand tool technology. She showe