Let Ω ⊆ R n+1 have minimal Gaussian surface area among all sets satisfying Ω = −Ω with fixed Gaussian volume. Let A = A x be the second fundamental form of ∂Ω at x, i.e., A is the matrix of first order partial derivatives of the unit normal vector at x ∈ ∂Ω. For any. Let A 2 be the sum of the squares of the entries of A, and let A 2→2 denote the 2 operator norm of A.It is shown that if Ω or Ω c is convex, and if eitherthen ∂Ω must be a round cylinder. That is, except for the case that the average value of A 2 is slightly less than 1, we resolve the convex case of a question of Barthe from 2001.The main tool is the Colding-Minicozzi theory for Gaussian minimal surfaces, which studies eigenfunctions of the Ornstein-Uhlenbeck type operator L = Δ − x, ∇ + A 2 + 1 associated to the surface ∂Ω. A key new ingredient is the use of a randomly chosen degree 2 polynomial in the second variation formula for the Gaussian surface area. Our actual results are a bit more general than the above statement. Also, some of our results hold without the assumption of convexity.