The contribution of the G_2 structure function to polarized deep inelastic scattering is slightly redefined in order to avoid kinematical zeros. Its strong Q^2-dependence implied by the Burkhardt-Cottingham (BC) sum rule naturally explains the sign change of the generalized Gerasimov-Drell-Hearn (GDH) sum rule. The status of the BC sum rule and implications for other spin processes are discussed.