Tired of the Late Night Trips To the Bathroom? If so, then you’re not alone. Most men over 40 years of age have at least some prostate enlargement, which causes frequent urination. The prostate is a walnut size organ that controls not only urination stream, but also sexual ejaculation. And yes, if your prostate is enlarged you’re likely to experience not only frequent trips to the bathroom at night, but sexual dysfunction as well.