Sperm delivery, as you can guess, refers to the journey sperm takes from the scrotum to the penis, and then outward. Men who suffer from sperm delivery problems can produce perfectly healthy sperm, but it is not included in their ejaculate, so a sperm analysis would show a total absence of sperm. Some possible causes are:No vas deferens. These are the tubes that normally carry sperm from the scrotum to the penis. Some men are born without these tubes, in which case it is called a congenital absence. The vas deferens can become blocked, either on one or both sides. This is often linked to medical problems like hernia and surgical interventions to treat them. Sperm is deposited into the bladder instead of exiting the penis. The man has had a vasectomy, and still produces sperm but it will not go anywhere due to the intervention.
Where azoospermia is caused by a sperm delivery problem of one kind or another, the person with azoospermia can have biological children in most cases, with the help of direct sperm extraction from the scrotum and fertility treatments like ICSI, or intracytoplasmic sperm injection. The first step to becoming a parent would be to determine the cause of the problem.