My research group is focusing on reproductive aspects of cancer and cancer treatment in young males. We have been studying a cohort of young men treated for childhood cancer and another cohort of men who have been cured for testicular cancer. We looked at impact of cancer and cancer treatment on semen quality of these men and, subsequently, also on production of the male sex hormone, testosterone. We found that 30-40% of these young cancer survivors presented with signs of testosterone deficiency – a condition linked with increased risk of metabolic and cardiovascular disease as well as osteoporosis. Our future studies will focus on the impact of cancer and cancer therapy on the health of the children of young male cancer survivors. This will be done by molecular studies o spermatozoa from cancer survivors as well as by use of national registries.