Contrary to what older studies may have indicated, there is new research to suggest that men who undergo vasectomy reversals after more than fifteen years have an equal or higher success rate at getting their female partners pregnant than do couples using in vitro fertilization.
Specifically, the study found that men who had their vasectomies reversed after 15 to 19 years achieved a 49% pregnancy rate. After 20 to 25 years, the pregnancy rate was 33%. While the age of the male did not appear to be a factor in pregnancy success, the age of his female partner was. The pregnancy rate was 64% for women younger than 30 years old and 28% for women older than 40 years old.
P.S. Improvements in techniques have led to much greater success with vasectomy reversals in recent years.