  Reflexive polytopes which have the integer decomposition property are of
interest. Recently, some large classes of reflexive polytopes with integer
decomposition property coming from the order polytopes and the chain polytopes
of finite partially ordered sets are known. In the present paper, we will
generalize this result. In fact, by virtue of the algebraic technique on
Gr\"obner bases, new classes of reflexive polytopes with the integer
decomposition property coming from the order polytopes of finite partially
ordered sets and the stable set polytopes of perfect graphs will be introduced.
Furthermore, the result will give a polyhedral characterization of perfect
graphs. Finally, we will investigate the Ehrhart $\delta$-polynomials of these
reflexive polytopes.
