Both gender bias studies and evidence-based medicine share the hypothesis of the existence of empirical uncertainty in medical practice. Nevertheless there is a lack of information regarding variations and sex, possibly due to androcentric reasons. Many biomedical studies--including randomised controlled trials--, have used men as the population's prototype and applied its conclusions to women. This approach is based in an erroneous assumption of equality between men and women. Gender bias research on therapeutic efforts are focused on hospital accessibility for the two sexes for equivalent health needs, comparison in delays and waiting times from the early symptoms to care, differential therapeutic strategies and differential consumption of, and expenditure on, medication. Also, research on over prescription of therapies are included in the health problems affecting only or mainly women. Gender bias in therapeutic efforts depends on the gender bias in the diagnostic efforts. Insofar as the probability of being treated once suffering a problem vanishes if for any cause the individual in question is excluded from the diagnostic process, or diminishes if the appropriate tests are not performed in the diagnostic process. The aim of this paper is to present an approach to the evidence of gender bias in therapeutic strategies in Spain.