Final answer:
All the methods listed (pedigree analysis, twin studies, adoption studies) are used in the study of human traits or disorders, with pedigree analysis being a common method for charting inheritance patterns.
Step-by-step explanation:
The question pertains to the methods used for studying the inheritance of human traits or disorders. Specifically, it asks which method is not normally used for this purpose. The answer is that all of the given methods (pedigree analysis, twin studies, adoption studies) are indeed utilized in the field of genetics to study human traits or disorders.
Pedigree analysis is particularly common and is used to chart the inheritance of traits over several generations, which assists in predicting the probability that offspring will inherit a genetic disorder. Twin studies and adoption studies are also important tools for geneticists; they help to distinguish the effects of genetics versus the environment on human characteristics.