  The role of reflection symmetry breaking for the character of the appearance
of replica symmetric spin glass state is investigated. We establish the
following symmetry rule for classical systems with one order parameter in the
replica symmetric mean field approximation. If in the pure system the
transition to the ordered phase is of the second order, then in the
corresponding random system the glass regime appears as a result of a phase
transition; if the transition in the pure system is of the first order, then
glass and ordered regimes grow continuously in the random system on cooling.
