Final answer:
Teratogenesis is the process in which teratogens, environmental agents like chemicals or toxins, cause birth defects in the developing fetus. The impact depends on the potency of the substance, the developing fetus's susceptibility, and the dose of exposure.
Step-by-step explanation:
The process in which outside agents cause birth defects in the fetus is known as teratogenesis. These outside agents, called teratogens, can be various environmental factors such as chemicals, biological substances, or physical factors that can lead to permanent defects in the developing embryo or fetus. Examples of teratogens include alcohol consumption during pregnancy, which is the leading preventable cause of intellectual disabilities in children in the United States. Other examples are drugs like thalidomide and environmental toxins like DDT.
The degree of teratogenicity depends on factors such as the potency of the substance as a mutagen, the susceptibility of the fetus to teratogenesis, and the dose of the teratogen to which the fetus is exposed. Teratogens can result in a range of birth defects, affecting physical characteristics such as limb development, cognitive abilities, and can lead to conditions like fetal alcohol spectrum disorders or neural tube defects like spina bifida due to nutritional deficiencies.