Ambiguity of genetic terms usage leads to their misinterpretation and learning difficulties. The content of some concepts is analyzed as well as haziness and mistakes in usage of corresponding terms such as gene, allele, genotype, phenotype, polymorphism, heritability, variability and few others. Limitations of the model dividing separately impact of the environment and genotype in a feature formation are explored. The interaction of the environment and hereditary material is suggested as basic factor of genetic and phonetic variability.