Henrietta was never informed that her cells were being taken for research. This raises the ethical issue of informed consent.
The informed consent process involves three key features:
(1) disclosing to potential research subjects information needed to make an informed decision
(2) facilitating the understanding of what has been disclosed
(3) promoting the voluntariness of the decision about whether or not to participate in the research. Informed consent must be legally effective and prospectively obtained.
From Informed Consent- FAQs, U.S. Department of Health and Human Services
The Tuskegee Study was another high profile case dealing with issues of informed consent, racial discrimination, and ethical treatment of research participants.