Final answer:
A teratogen is any agent that causes damage to a developing embryo or fetus, with effects depending on various factors such as potency and exposure duration. Alcohol is a well-documented teratogen that can lead to a range of lifelong conditions known as fetal alcohol spectrum disorders.
Step-by-step explanation:
A teratogen is accurately described as any environmental agent, including biological, chemical, or physical, that can cause damage to the developing embryo or fetus. This includes substances like alcohol, cigarette smoke, illicit drugs, prescription medications, and certain diseases like rubella that pregnant mothers can pass to the developing fetus. The severity and type of birth defects caused by teratogens can vary widely and depend on factors such as the potency of the teratogen, the susceptibility of the fetus, the dosage and duration of exposure to the teratogen, and the specific time during development when exposure occurs.
Among the wide range of potential teratogens, certain substances have been well-documented to cause significant developmental problems. For example, alcohol consumption during pregnancy can lead to fetal alcohol spectrum disorders (FASD), which include a range of physical, cognitive, and developmental difficulties that persist into adulthood. Other well-known teratogens include illicit drugs like cocaine and heroin, as well as prescription medications that can negatively impact fetal development when taken during pregnancy.