Which statement correctly defines a teratogen and provides valid examples?

Which statement correctly defines a teratogen and provides valid examples?

• A. Teratogens are substances that have no effect on fetal development.
• B. Teratogens are nutrients required for healthy fetal growth.
• C. Teratogens are agents that always cause birth defects.
• D. Teratogens are agents that can disturb fetal development; examples include alcohol and nicotine.

Answer: (D)

Teratogens are agents that can disturb fetal development, and their effects depend on timing and dose during pregnancy. They don’t always cause birth defects, but exposure can lead to a range of outcomes from growth issues to neurodevelopmental problems. Alcohol is a classic example, capable of causing fetal alcohol spectrum disorders, while nicotine exposure from smoking is linked to reduced birth weight and other risks. The other statements aren’t accurate because teratogens do not have no effect, they are not nutrients, and they do not always cause defects.

Teratogens are agents that can disturb fetal development, and their effects depend on timing and dose during pregnancy. They don’t always cause birth defects, but exposure can lead to a range of outcomes from growth issues to neurodevelopmental problems. Alcohol is a classic example, capable of causing fetal alcohol spectrum disorders, while nicotine exposure from smoking is linked to reduced birth weight and other risks. The other statements aren’t accurate because teratogens do not have no effect, they are not nutrients, and they do not always cause defects.