The 2 S -1 S transition in light muonic atoms is very sensitive to parity violation correlations induced via neutral currents. Observables depending on these transitions such as the photon polarization and the angular correlation between the emitted radiation and the atom polarization are a clear signal of weak neutral currents in atoms. We find the relation between the lepton and quark couplings and these observables emphasizing the effect of the nuclear spin. The results expected in muonic, atoms μ- 4 He and μ- 3 He are given.This work has been supported in part by CICYT, under grant AE-0021. Two of us (J.B. and J.V.) are indebted to Ministerio de Educación y Ciencia and to C.S.I.C., respectively for the research fellowships.Peer reviewed