  To resolve the current ambiguity in the splitting function corresponding to
the quark transversity distribution $h_1(x)$, we calculate $h_1(x)$ for a
dressed quark in light-front Hamiltonian perturbation theory. Our result agrees
with the expected form of the splitting function found in the literature and
disagrees with the recent calculation in \cite{kuhn}. We emphasize the
importance of quark mass in $h_1(x)$ in perturbative QCD and show its
connection with a part of $g_T$.
