Family Replication in the Dual Standard Model
  The family replication problem is addressed in the context of the dual standard model. The breaking of a simple grand unified group to $[G_{low} \times H_1 \times H_2 \times H_3]/Z_5^3$ and then further to $G_{low}$, produces a spectrum of stable monopoles that fall in three families each of whose magnetic quantum numbers correspond to the electric charges on the fermions of the Standard Model. Here $G_{low}=[SU(3) \times SU(2) \times U(1)]/Z_6$ is the symmetry group of the standard model above the weak scale, and $H_i$ are simple Lie groups which each have a $Z_5$ symmetry in common with $G_{low}$. 
Hong Liu, Glenn D. Starkman, Tanmay Vachaspati (Case Western Reserve   University)