My hypothesis is that higher female sensitivity to increased n-6 polyunsaturated fatty acids and their carcinogenic effect may contribute to the recent Israeli 'cancer shift' over heart disease mortality (23.1 vs. 22.3%, 1999). High n-6 polyunsaturated fatty acid intake was the presumed dietary risk underlying the 'Israeli paradox', the unexpected gap between 'ill' health and 'good' diet. Scientific literature and population health surveillance reports were reviewed. Cancer death rates for Israeli Arabs, who consumed a more traditional Mediterranean diet - more monounsaturated fatty acids, mostly olive oil, and less n-6 polyunsaturated fatty acids - are still 1.1-1.7 times (men-women) lower than in Israeli Jews, but are increasing faster (23.6 and 5.1% vs. 5.3 and -3.3%, 1980-2000), concurrently with dietary 'Israelization' - specifically, increased intake of n-6 polyunsaturated fatty acids. Israeli-Jewish women attained an earlier, much larger (29 vs. 7%, 1999) 'cancer : heart disease mortality shift' (ratio >1.0), ranked much worse for cancer (15th/44 European countries) than men (37th) and heart disease (38th and 34th, respectively), and had much higher cancer prevalence (1 : 3) than Israeli-Arab women (1 : 6), though dietary compositions were similar, save for higher n-6 polyunsaturated fatty acid and polyunsaturated fatty acid : monounsaturated fatty acid ratio. Population studies of Israeli Jews, Arabs, and women support the association of high n-6 polyunsaturated fatty acid intake with increased cancer risk and higher female sensitivity. Research findings suggest that gender and sex hormones may influence n-6 polyunsaturated fatty acid metabolism and carcinogenesis. This appears to be the first time gender has been proposed to modulate national cancer epidemiology, suggesting implications for differential nutritional prevention, warranting further research.