We describe paternal exposure and counselling in a selected population calling to an Italian Teratology Information Service (TIS). The majority of callers asked for paternal drug exposure (76%, drugs except chemotherapy) and treatment for cancer (17%, chemotherapy and/or radiotherapy). Others asked for exposure to diagnostic radiations (4%), recreational drugs (2%) and occupational chemicals (1%). Among paternal drugs neurological compounds, immunosuppressive drugs and antiviral agents were the main reasons for calling. In humans, there are no evidences of birth defects after paternal exposures, but to minimize any possible risk, counselling in men exposed to radio and chemotherapy should recommend delaying conception for at least 3 months after the end of the therapy. Male patients treated with drugs, whose teratogenic potential has been well assessed or suspected for maternal exposure, should be advised to practice effective birth control during therapy and up to one or two cycles of spermatogenesis and to avoid semen contact with vaginal walls during first trimester of pregnancy.