We establish a Liouville type result for stable solutions for a wide class of second order semilinear elliptic equations in R n \mathbb {R}^{n} with sign-changing nonlinearity f f . Under the hypothesis that the equation does not have any nonconstant one dimensional stable solution, and a further nondegeneracy condition of f f at its zero points, we show that in any dimension, stable solutions of the equation must be constant. This partially answers a question raised by Dancer.