As one might expect, infertility in men can be due to many different causes. Sometimes, multiple factors may be contributing to a man's infertility. Testis development during infancy and childhood infections such as mumps can have fertility ramifications many years later.
There are a few additional conditions that may affect a man’s infertility, including:
- Current or previous medical conditions and cancers—often previously undetected—might affect sperm production
- Men who undergo chemotherapy or radiation treatments can have long-standing testicular damage
- Environmental or work-related exposures can affect testicular function
- Various hormonal abnormalities can have large effects on sperm production
- Anatomical conditions such as varicocele can lower sperm counts or affect sperm function.
Sometimes, even though sperm is being produced normally, a blockage might be preventing the sperm from reaching the ejaculate. Such blockages can be due to previous infections, previous surgical procedures, or congenital causes. Finally, other men might not be able to reach orgasm, or might have functional defects preventing the proper outflow of sperm with orgasm.