How Far Can the SO(10) Two Higgs Model Describe the Observed Neutrino Masses and Mixings ?

Can the SO(10) model with one {\bf 10} and one {\bf 126} Higgs scalars give the observed masses and mixings of quarks and leptons without any other additional Higgs scalars? Recently, at least, for quarks and charged leptons, it has been demonstrated that it is possible. However, for the neutrinos, it is usually said that parameters which are determined from the quark and charged lepton masses cannot give the observed large neutrino mixings. This problem is systematically investigated, and it is concluded that the present data cannot exclude SO(10) model with two Higgs scalars although it cannot give the best fit values of the data.