Data will be collected by questionnaires for all subjects on their contraceptive and STI history, key demographic, social and behavioural factors relevant to condom failure risk at baseline. At crossover and trial end the rate and types of condom failure, side effects and acceptability of additional spermicide, and health service and subject costs are collected. A random sample of subjects also participate in a detailed semi-structured interview at the end of the study, covering their recent experiences of condom failure, and opinions about condoms in general, including the use of additional spermicide. These qualitative findings will then be discussed in patient and professional focus groups as a proxy for respondent checking and data triangulation.