When a man and his partner are struggling to conceive, or he's staring at the reality of a serious medical challenge, difficult questions about fertility need to be addressed, including his options for preserving sperm.

"Most often, I have worked with men who were freezing their sperm in relation to infertility treatment they were actively undergoing with their partner, such as IVF [in vitro fertilization]," said Claire O'Neill, a certified andrology and embryology lab scientist based in New York. "Also, if they were about to start cancer treatment. Chemotherapy treatment is highly damaging to sperm, so men who may want to have children in the future may choose to freeze their sperm as a precaution."

Sperm banking or freezing, also called sperm cryopreservation, is a type of fertility preservation, according to the National Cancer Institute. While looming chemo is a primary driver of many people's decision to bank sperm, there are other reasons that exist.

Barrett Cowan, M.D., has specialized in treating men with infertility for more than 20 years and is the