Have there been any "chopstick gene" mistakes in genetics?
Have a look at this time article from a couple years ago. 

A concept that you should think about is nature vs nurture. You can think of nature (your genetics) as controlling part of the potential of what you could become (for example, many long distance athletes have genetics that are beneficial for their sport) where as nurture encapsulates the environment that you grow up in (a nutritionally deficient child will not reach maximum potential height that you might predict based on genetics alone).

When scientists are studying a gene in relation to a phenotype, they statistical methods to determine how much a genotype contributes to a phenotype. This process would minimize these types of fallacies since different alleles in different populations would be considered. However, sampling biases can occur and most human variation studies are done on people of european, asian, and african descent.