In men, the infection may cause symptoms such as urinary frequency, urgency, painful urination, nocturia, urethral irritation, production of urethral discharge, difficulty in urination and, less commonly, prostatitis and tenderness and epididymitis, and possibly male infertility. Some scholars believe that Trichomonas vaginalis can engulf sperm and the increased discharge after infection affects sperm viability, leading to male infertility.