We propose T13 = Z13 Z3 as the underlying non-Abelian discrete family symmetry of the asymmetric texture presented in [1]. Its mod 13 arithmetic distinguishes each Yukawa matrix element of the texture. We construct a model of effective interactions that singles out the asymmetry and equates, without finetuning, the products of down-quark and charged-lepton masses at a GUT-like scale. *