I am just writing to share my negative experience with vasectomy.

When you have a vasectomy, your body continues to produce sperm, but without an outlet it is reabsorbed into the body. In a percentage of cases, men develop antibodies to their own sperm, an autoimmune reaction which can lead to conditions such as lupus and multiple sclerosis. See http://www.nichd.nih.gov/publications/pubs/vasect.htm

In my case, I had a vasectomy done in 1991, and about ten years later I developed lupus. No "proof" that one caused the other, but too much of a coincidence. I am in the process of arranging to have my vasectomy reversed. Only a small percentage of men have such a negative reaction to a vasectomy, I was unlucky. However, there are lesser side effects such as plain out pain, or sexual dysfunction. The most anti-vasectomy website is http://dontfixit.org - check it out, it has tons of links.

A lot of guys have vasectomies and claim no problems. I don't know. Could be they are having some minor problems that are not generally attributed to vasectomies and they don't know it. All I know personally is that myself and three of my buddies had vasectomies in the early 1990s and we all ended up with problems of one sort or another, though some took many years to manifest.

Perhaps if you are a relatively healthy male your system can handle a vasectomy without too much trouble, but if your health is compromised, it can put a real stress on your immune system (amongst other possible problems). One of my above mentioned buddies developed allergies for the first time in his life soon after his vasectomy.

I believe the key to birth control is to develop a better condom, one that is somehow more sensitive for the man yet less liable to break or slip off. At the moment, barrier is the only method that doesn't mess with our hormonal or immune systems in one way or another.