Final answer:
The term used to refer to an individual who first brings a genetic condition to the attention of researchers when creating a pedigree chart is 'proband'. This allows geneticists to use pedigree analysis to study inheritance patterns of genetic diseases, especially when test crosses are not ethical or practical in humans.
Step-by-step explanation:
In studies of human genetics, when pedigrees are developed to trace the inheritance of a trait, the individual who first brings the condition to the attention of a scientist or physician is referred to as the proband. This term is especially relevant when discussing familial patterns of inheritance and trying to determine whether a person carries a gene for a recessive genetic disorder and the associated risks of passing it on to offspring. Unlike in plant or animal studies where test crosses are used to reveal the genotype of individuals, human geneticists conduct pedigree analysis, which relies on the tracking of phenotypic traits through generations to infer genotypic information.
An example of this approach is when neither parent shows signs of a disorder but their child does; this indicates that both parents must be heterozygous carriers. This type of analysis is important because most diseases show a multigenic pattern of inheritance and environmental factors may also play a role. However, only for some single-gene disorders, like cystic fibrosis, can genetic testing provide definitive risk assessments.