From  The University of Iowa-

Vasectomies can be reversed even after very long periods of time, sometimes after more than 25 years. Sperm are constantly being produced in men and even after time, there should be viable sperm. However, the success of the reversal, in terms of achieving a pregnancy, is dependent upon the experience of the surgeon, the age and fertility status of the female partner, and the length of time since the vasectomy. Read More