Due to substitution, elimination or addition of amino acids, different genetic milk protein variants vary in their molecular properties, i.e. net electrical charges, hydrophobicity and three-dimensional structure along the peptide chain. These differences influence the technological properties of the milk to a varying extent. Despite a lot of contradictory results over the years within this study field, it is generally agreed that the B variants of κ-casein and β-lactoglobulin are correlated to higher casein content, better curd firmness and higher cheese yield than the A variants. The influence of other genetic variants is also discussed in the paper.