An evaluation of predisposing factors for testis cancer in Ireland.

All testis cancer in Ireland (1980-1985) was analysed (n = 240). Incidence was highest in young adults (5.8/10(5)/year in those aged 25-34 years) with a moderate level in the elderly (1.8/10(5)/year in those over 75 years). Associations elsewhere with maldescent and social class were confirmed but cryptorchidism (12%) was more common than expected. Significant infertility was not identified. Associations with urban domicile (77%, p = 0.001), mental handicap (2.8%, p less than 0.05), recent vasectomy (1.2%, p = 0.009) and certain occupations were observed.