Ironically, racial “purity” actually encourages a rise in mental and physical deficiencies like severe mental deficiencies, reduced fertility (ironic), high infant mortality rates, high miscarriage rates, growth issues leading to reduced size (even more ironic), high levels of heart conditions, cancer, diabetes, cosmetic and functional deformities, and reduced immune function. If you want to have strong children, mixed race is the way to go, from a purely genetic standpoint