My father had a vasectomy in his late 30s. He had a heart attack at 51 (since he was a smoker, it's hard to pin that on vasectomy). Later, he developed an abdominal aortic aneurysm. He's 75 now and bed-ridden in a nursing home from pituitary tumors and normal pressure hydrocephalus (water on the brain). They believe the tumors started 10 years ago. They have been secreting hormones and totally screwing up his endocrine system. Docs now postulate this led to his massive weight gain from 250 lbs. to over 400.
The list of things not wrong with my father is shorter than the list of things that are wrong with him. He was placed on hospice 4 months ago due to the cornucopia of problems.
My paternal grandfather lived to the age of 85 and my paternal grandmother lived 'til 95. Both developed late-in-life cancer, but lived active, healthy lives into their early 80s and 90s. In other words, my father had good genes. I'm convinced the vasectomy started him downhill.