Latency period: Cancer can take decades to develop after exposure to a carcinogen, making it difficult to establish a direct link. Multiple exposures: People are often exposed to multiple potential carcinogens, complicating the identification of specific causes. Ethical considerations: Conducting experiments on humans to test carcinogenicity is not ethical, so researchers rely on observational studies and animal models. Confounding factors: Other variables, such as genetics or lifestyle, can confound the relationship between a carcinogen and cancer.
