- difficulty conceiving
- The inability to produce children.
Definition from: Physician Data Query via Unified Medical Language System at the National Library of Medicine
- Not fertile; especially : incapable of or unsuccessful in achieving pregnancy over a considerable period of time (as a year) in spite of determined attempts by heterosexual intercourse without contraception <infertile couples> <an infertile male with a low sperm count> <an infertile female with blocked fallopian tubes>.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
Related discussion in the Handbook
See also Understanding Medical Terminology.