Before a bone marrow transplant, preparatory treatments like chemotherapy or radiation can significantly affect your fertility. A semen analysis is recommended to check your fertility status and allow you to freeze and store your sperm (sperm banking) for the future. Regarding Hepatitis B, the transplant suppresses your immune system, which can cause the virus to reactivate. To safely prevent or treat this, doctors prescribe daily antiviral medications. Highly effective generic options include entecavir or tenofovir, which protect your liver while your new immune system recovers. Your medical team will closely monitor your health to keep you safe and comfortable throughout your recovery.