Some populations are considered vulnerable if there are legitimate concerns about their competency to understand information presented to them and make reasoned choices. These populations include people with psychiatric, cognitive, or developmental disorders and substance abusers.

Children are considered a vulnerable population because they develop decision making skills and related competencies over time.

Other vulnerable populations include those who are institutionalized and may be not be free to choose without coercion or undue influence, e.g. prisoners.

Pregnant women are considered a vulnerable population, as are fetuses; however, special protections for these two groups are geared toward medical research.

In broadest terms, the special protections in the regulations define levels of risk with associated review and consent requirements. For example, research with children that puts them at risk and offers no direct benefit for the children must secure the consent of both parents. Much research in the social and behavioral sciences is of minimal risk and thus the additional requirements may not apply.

Investigators may review the specific federal regulations designed to provide special protections for:

1. Children
2. Pregnant women, fetuses, and neonates
Prisoners