  We investigate an interesting correlation among dark matter phenomenology,
neutrino mass generation and GUT baryogenesis, based on the scotogenic model.
The model contains additional right-handed neutrinos $N$ and a second Higgs
doublet $\Phi$, both of which are odd under an imposed $Z_2$ symmetry. The
neutral component of $\Phi$, i.e. the lightest of the $Z_2$-odd particles, is
the dark matter candidate. Due to a Yukawa coupling involving $\Phi$, $N$ and
the Standard Model leptons, the lepton asymmetry is converted into the dark
matter asymmetry so that a non-vanishing $B-L$ asymmetry can arise from
$(B-L)$-conserving GUT baryogenesis, leading to a nonzero baryon asymmetry
after the sphalerons decouple. On the other hand, $\Phi$ can also generate
neutrino masses radiatively. In other words, the existence of $\Phi$ as the
dark matter candidate resuscitates GUT baryogenesis and realizes neutrino
masses.
