Causes of azoospermia - 4

4) Anejaculation: 
    - total failure of seminal emission into the posterior urethra. 
    - Rare

5) Retrograde ejaculation: 
  - substantial propulsion of seminal fluid from the posterior urethra into the bladder. 
  - Accounts for 0.3–2.0% of male fertility problems

(4) and (5) may result from:

1. Spinal cord injury
2. Transurethral prostatectomy – only 7% of men retain ejaculation
3. Retroperitoneal lymph node dissection
4. Diabetes mellitus
5. Transverse myelitis
6. Multiple sclerosis
7. Psychogenic / idiopathic disorders