For some men, cancer treatment leads to permanent infertility. For others, treatment may stop or slow sperm production for years before it returns. In general, men who receive higher doses of radiation therapy or chemotherapy need to wait longer to regain sperm production. These men also have a higher risk of permanent infertility.
Other factors, such as existing fertility issues or age, also affect fertility. For example, men older than 40 are less likely to regain fertility. But, younger boys who receive treatment for cancer before puberty may not have as much sperm damage. However, stronger treatments may still cause permanent future infertility in children. Such treatments include chemotherapy for a bone marrow/stem cell transplant.
It is important to note that although cancer treatments may make it less likely, a pregnancy can still occur. Many doctors recommend that men who had chemotherapy or radiation treatment wait 6 months so their sperm has enough time to repair. Talk with your doctor about the best time frame for you.