An agent that may cause physical defects in a developing embryo or fetus upon exposure during pregnancy is called what?

• A. Mutagen
• B. Epidemiology
• C. Teratogen
• D. Carcinogen

Answer: (C)

Teratogen is the term for an agent that may cause physical defects in a developing embryo or fetus when exposure happens during pregnancy. This category is focused on birth defects and developmental problems that arise because the developing fetus is exposed to the agent during critical periods of growth, especially during organ formation. Different from this, a mutagen is any factor that causes genetic mutations, which can have various consequences but isn’t defined specifically by causing congenital defects. A carcinogen refers to agents that can promote cancer. Epidemiology, meanwhile, is the study of how diseases spread and affect populations, not a type of agent. Understanding teratogens helps explain why certain exposures during pregnancy are avoided to protect fetal development.