Azoospermia is a medical term; it means lack of sperms in the ejaculate. There are two reasons for this conduction. It could be due to obstruction (Obstructive Azoospermia) where there is a blockage in the sperm carrying tubes or due to sperm production in the testis (Non-Obstructive Azoospermia). In other words, in obstructive azoospermia the problem is the transport of the sperms, in non-obstructive azoospermia there is a problem with production.