The principle of inheritance of multifactorial traits (MTs) relies on the presence of a considerable number of genetic markers, with each marker contributing to the probability of developing those traits. This work proposes an algorithm for the selection of DNA markers that could be used to devise a prognostic test system for the assessment of individual predisposition to MTs. The method is based on the selection of genetic markers that have demonstrated a statistically significant association with an MT in question and have been described as functionally significant polymorphisms that affect MT development. If the functional significance of a polymorphism has not been described so far, then to be reliably associated with an MT, this polymorphism is expected to achieve genome-wide significance in one of the studies and such significance must be confirmed in an independent sample. Works used to assess the association of genetic markers with MTs are expected to meet the proposed criteria depending on the study type.