Where is the best sperm located?

This is a question I am often asked by my patients who need to undergo a sperm retrieval procedure. The answer is. . .it depends. Actually it depends on the following factors:

• Obstructive Azoospermia: Patients with blockages but otherwise normal sperm production within the testicle can expect to have healthy sperm in the epididymis and the testicle. Sperm from both areas will work fine.
• Non-obstructive Azoospermia: These patients don't produce sperm in sufficient number to reach the ejaculate or even, in most coses, the epididymis. Sperm must be retrieved in these men from the testicle.
• Embryologist Preference: Some embryologists(the person who actually performs the ICSI/IVF) have more experience with epididymal sperm as opposed to testicular sperm and thus prefer epididymal sperm. Epididymal sperm, in general, is more motile than testicular sperm, and embryologists tend to favor more motile sperm over less motile sperm.
• Urologist Preference: Some cases of severe male factor infertility require specialized techniques to locare and harvest sperm in sufficient quantities to be of use to the embryologist. In addition, in these cases, the urologist must be availabe "on-call" to perform the procedure. Not all urologists have that degree of expertise or scheduling flexibility.