What is the best description of a chemical that causes damage to a fetus?

A chemical that causes damage to a fetus is best described as a teratogen. Teratogens are substances that can cause congenital malformations or developmental issues in an embryo or fetus when exposure occurs during pregnancy. These substances can affect the development of various organs and systems, leading to physical, cognitive, or functional abnormalities, depending on the timing and level of exposure during fetal development.

In the context of fetal health, teratogens can include certain medications, alcohol, toxic chemicals, and some infectious agents. Their teratogenic effects are often most pronounced during specific periods of fetal development, highlighting the need for caution during pregnancy regarding potential exposures.

While mutagens affect the DNA structure and can lead to genetic mutations, and carcinogens are substances that increase the risk of cancer, they do not specifically target the developmental processes of the fetus in the same way teratogens do. Endocrine disruptors interfere with hormonal systems and can affect reproductive health, but they do not exclusively cause structural or developmental damage to a fetus as teratogens do. Therefore, the distinguishing characteristic of a teratogen is its direct impact on fetal development, making it the most accurate description in this context.