Mendelian randomization borrows statistical techniques from economics to allow researchers to analyze the effects of the environment, drug treatments, and other factors on human biology and disease. Taking advantage of the fact that genetic variation is randomized among children from the same parents, it allows genetic variants known to influence factors like alcohol consumption or low-density lipoprotein (LDL) levels to be used as instrumental variables that can disentangle the effects of these factors on outcomes such as pregnancy or cardiovascular disease, respectively. There are caveats to analyses using Mendelian randomization and related techniques that researchers should be aware of, but they are increasingly powerful tools for solving problems in epidemiology and human biology.