No it's not to prevent testicular cancer. Nolva, clomid, and tore are serms, they are commonly used for breast cancer in females. You have nolva to take after your cycle to help the body start producing testosterone again. Even taking dbol only will disrupt the hpta and possibly shut down completely so you need help getting it started again as quick as possible to regain hormone balance. Without your body producing test, you will begin to loose muscle gained and feel like ass. This is why you start with test because you are replacing what is shut down. And ofcourse all it's other benefits.