  In these proceedings, we propose an extraction of the valence transversity
parton distributions. Based on an analysis of pion-pair production in
deep-inelastic scattering off transversely polarized targets, this extraction
of transversity is performed in the framework of collinear factorization. The
recently released data for proton and deuteron targets at HERMES and COMPASS
allow for a flavor separation of the valence transversities, for which we give
a complete statistical study.
