Gender-Diversity is the most effective change factor resulting in the transformation of organisation-, leadership-, and HR-development. It is not enough to enhance the number of women at senior levels (recruiting, retention, promotion). Instead, what it requires is a company-wide change of awareness and leadership, thus enabling a sustainable cultural change. To become and be a mother is often contrary to female management careers (leaky pipeline phenomenon). As a result companies lose vital leadership competences and leadership development investments.