The Standard Model exhibits a (−1) symmetry, where F is the fermion number operator counting how many fermions are in a state. Since all particles in the Standard Model satisfy F = B + L, the discrete symmetry is also part of the e continuous symmetry group. If the parity operator satisfied P = (−1), then it can be redefined to give a new parity operator satisfying P = 1. But if the Standard Model is extended by incorporating Majorana neutrinos, which have F = 1 and B + L = 0, then the discrete symmetry (−1) is no longer part of the continuous symmetry group and the desired redefinition of the parity operator cannot be performed. Instead it satisfies P = 1 so the Majorana neutrinos would have intrinsic parities of ± i.