- Hx erectile problems? If yes, see above under "erectile dysfunction"
- Blocked sperm delivery system→ injury, surgery, infection affecting vas deferens
- Congenitally absent vas deferens→ Cystic Firbrosis
- Partners health/issues (infertility Etiology 1/3 male, 1/3 female, 1/3 mixed)
- Idiopathic