Gamma rays have significant effects on human cells, primarily known for their ability to kill cells and induce mutations. While gamma rays can damage DNA and genes, they may also allow mutated cells to proliferate, leading to serious health issues. Historical context highlights the aftermath of the Hiroshima and Nagasaki bombings, where survivors were advised against having children due to the risk of passing on genetic mutations. Despite the potential for harm, gamma rays are also beneficial in medicine, particularly in the treatment of cancer, where they are employed to target and destroy malignant cells.