Whereas the goals of gender-mainstreaming were steadily set in many fields especially related to the environment, welfare, and development since the late 1990s, the pace of developing the argument on gender balance in the international arena of nuclear disarmament was very slow. Under such circumstances, United Nation Security Council resolution 1325 (2000) was surely a landmark because the necessity of gender-consciousness was clearly expressed in the field of security issues. The resolution 1325 mainly aimed at promoting gender equality in peacebuilding process after the internal armed conflicts, although activists and experts started to link the gender and the interstate matters of nuclear disarmament, in line with the spirit of the resolution. Nonetheless, there were still few discussions regarding the gender equality in nuclear disarmament for a decade after that resolution was adopted. It was the presentation by Ms. Mary Olson, policy expert at Nuclear Information and Resource Service who changed the situation. Her presentation at the Vienna Conference on the Humanitarian Impact of Nuclear Weapons in December 2014, demonstrated the evidence that radiation damage could be more serious to women. Her argument encouraged Ireland to advocate gender equality more progressively in the policy field of nuclear disarmament by presenting a working paper titled “Gender, Development and Nuclear Weapons” to the 2020 NPT Review Conference Preparation Committee held in May 2017. It is also worth mentioning that Olson made a speech at the Vienna Conference on the Humanitarian Impact of Nuclear Weapons that facilitated a discussion for the adoption of the Treaty on the Prohibition of Nuclear Weapons. In the preamble of this treaty, significance of gender-mainstreaming was clearly stipulated. Meanwhile, International Law and Policy Institute (ILPI) and United Nations Institute for Disarmament Research (UNDIR) jointly published an influential report “Gender, Development and Nuclear Weapons” in 2016. Gender conscious arguments are considered to be getting more observable from thereafter.