  Spiral galaxies show axial symmetry and an intrinsic 2D-chirality.
Environmental effects can influence the chirality of originally isolated
stellar systems and a progressive loss of chirality can be recognised in the
Hubble sequence. We point out a preferential modality for genetic galaxies as
in microscopic systems like aminoacids, sugars or neutrinos. This feature could
be the remnant of a primordial symmetry breaking characterizing systems at all
scales.
