Scientists studied how to help boys and men with cancer preserve their fertility. Cancer treatment can harm sperm, affecting future chances of having a baby. Saving sperm before treatment can make patients feel better emotionally. New techniques in sperm freezing and assisted reproduction help males become fathers later even if their sperm quality is poor. Young boys, not yet at puberty, may also have options in the future for preserving fertility. Unfortunately, not many cancer patients use sperm freezing before treatment even when it's available. Doctors need to talk to patients early on about fertility choices to ensure they have the best chance to have children later.