Generation of acceptor-like electron traps in gate oxide is an important source for the instability of MOS transistors. Agreements have not been reached on the dominant damaging species. When injected electrons were orders of magnitude higher than injected holes, it was proposed that hydrogen release and its subsequent transportation through the oxide dominated the generation. It was also reported that holes were more efficient in creating electron traps than electrons. However, the physical process for the hole-induced generation is not clear. This work is focused on one issue: is the release and subsequent transportation of hydrogenous species also important for hole-induced electron trap generation? Effects of hydrogenous species released near the two interfaces and in the bulk of oxides are examined. It is found that the release and subsequent transportation of hydrogenous species are not important for the hole-induced generation. Results support that holes can interact directly with the oxide to generate electron traps without going through hydrogen as intermediate species.