Males under the age of 25 diagnosed with cancer are less likely to have children than those without the disease.
There is also less likelihood that cancer survivors get married than their peers without a cancer diagnosis.
Nevertheless, if they marry, they are three times as likely to turn to assisted fertilization to have children as males with no cancer diagnosis.
Reduced paternity in male cancer patients was observed especially among survivors of testicular cancer, brain tumours, lymphoma, leukaemia and bone cancer.
"These finds are important for male cancer survivors, seeing as we can identify groups at risk of having reproduction problems," said lead author Maria Winther Gunnes from the University of Bergen (UiB) in Norway.
Children of those who have survived cancer do not have an increased risk of perinatal death or congenital anomalies. Similarly, there were no indications of increased risk of preterm birth or low birth weight, the researchers said.
Also, the number of survivors after treatment of cancer in childhood, adolescence and young adulthood has steadily increased up to 80 percent over the past decades, due to improvements in treatment regiments and supportive care.
The findings are detailed in the British Journal of Cancer.
The researchers conducted a cohort study of all Norwegian men born between 1965 and 1985 to find out what cancer at a young age means for reproduction and marriage among male survivors of cancer in childhood, adolescence and young adulthood.
