Discuss teratogens. Why does the harm from teratogens vary, and what are some long-term consequences of exposure?

What will be an ideal response?

The term teratogen refers to any environmental agent that causes damage during the prenatal period. Scientists chose this label (from the Greek word teras, meaning "malformation" or "monstrosity") because they first learned about harmful prenatal influences from cases in which babies had been profoundly damaged. But the harm done by teratogens is not always simple and straightforward. It depends on the following factors:
– Dose. Larger doses over longer time periods usually have more negative effects.
– Heredity. The genetic makeup of the mother and the developing organism plays an important role. Some individuals are better able than others to withstand harmful environments.
– Other negative influences. The presence of several negative factors at once, such as additional teratogens, poor nutrition, and lack of medical care, can worsen the impact of a single harmful agent.
– Age. The effects of teratogens vary with the age of the organism at time of exposure. In the period of the zygote, before implantation, teratogens rarely have any impact. If they do, the tiny mass of cells is usually so damaged that it dies. The embryonic period is the time when serious defects are most likely to occur because the foundations for all body parts are being laid down. During the fetal period, teratogenic damage is usually minor. However, organs such as the brain, ears, eyes, teeth, and genitals can still be strongly affected.
The effects of teratogens go beyond immediate physical damage. Some health outcomes are delayed and may not show up for decades. Furthermore, psychological consequences may occur indirectly, as a result of physical damage. Over time, parent–child interaction, peer relations, and opportunities to explore may suffer. Furthermore, prenatally exposed children may be less resilient in the face of environmental risks, such as single parenthood, parental emotional disturbance, or maladaptive parenting. As a result, their long-term adjustment may be compromised.