Mendelian randomization (MR) is an epidemiological method that uses the properties of genetic variants inherited from parents to detect causal relationships between exposure and disease[1][3]. The basic principle of MR is gene-environment equivalence, which means that a change in phenotype caused by a genetic variant has the same effect on the outcome as a change caused by environmental factors[1][3]. The method relies on Mendel's laws of segregation and independent inheritance, according to which genetic variants are transmitted randomly and independently of the environment and other genetic factors[1][3]. MR works similarly to a natural randomized controlled trial, where individuals are randomly assigned to groups based on the alleles inherited from their parents[3]. This method makes it possible to identify causal relationships in observational studies without the influence of reverse causality or confounding factors that often distort the results of conventional epidemiological studies[4]. Correct application and critical consideration of the principle of gene-environment equivalence is essential for quality MR studies[1].