  A specific class of gauge theories is geometrically described in terms of
fermions. In particular, it is shown how the geometrical frame presented
naturally includes spontaneous symmetry breaking of Yang-Mills gauge theories
without making use of a Higgs potential. In more physical terms, it is shown
that the Yukawa coupling of fermions, together with gravity, necessarily yields
a symmetry reduction provided the fermionic mass is considered as a globally
well-defined concept. The structure of this symmetry breaking is shown to be
compatible with the symmetry breaking that is induced by the Higgs potential of
the minimal Standard Model. As a consequence, it is shown that the fermionic
mass has a simple geometrical interpretation in terms of curvature and that the
(semi-classical)"fermionic vacuum" determines the intrinsic geometry of
space-time. We also discuss the issue of "fermion doubling" in some detail and
introduce a specific projection onto the "physical sub-space" that is motivated
from the Standard Model.
