 Comparison: Omega 3 fats plus folic acid will be compared with placebo plus folic acid in men age 35 to 55 attempting pregnancy with normal or mildly impaired semen quality. They will fill out dietary questionaires, questionaires regarding sexual function, and will have measurements of serum nitrates, blood pressure, and semen quality before and during use of these nutritional supplements. In men continuing on both omega 3 fats and folic acid, we will compare the effects of a sub-therapeutic dose of a PDE 5 inhibitor versus placebo on their sexual function. 