  We explore the possibility that the observed baryon asymmetry of the universe
is the result of an earlier phase transition in which an extended gauge sector
breaks down into the $SU(3)_C \times SU(2)_L \times U(1)_Y$ of the Standard
Model. Our proto-typical example is the Topflavor model, in which there is a
separate $SU(2)_1$ for the third generation from the $SU(2)_2$ felt by the
first two generations. We show that the breakdown of $SU(2)_1 \times SU(2)_2
\to SU(2)_L$ results in lepton number being asymmetrically distributed
through-out the three families, and provided the SM electroweak phase
transition is {\em not} strongly first order, results in a non-zero baryon
number, which for parameter choices that can be explored at the LHC, may
explain the observed baryon asymmetry.
