Gender equality is essential to social justice and sustainable development in the higher education sector. An important aspect thereof is to promote equal opportunities for academic careers. This study investigates the current situation and possibilities for improvement in this regard from the perspectives of mid-career scientists in a sustainability-oriented university department. A survey of scientists from the postdoctoral to adjunct professor level (N = 82) in the Department of Environmental Systems Science (D-USYS) of ETH Zurich (Swiss Federal Institute of Technology Zurich) was thus conducted to investigate judgements, experiences, and ideas for improvement concerning equal career opportunities. About 90% of the respondents perceived no disadvantages based on gender, ethnicity, race, or faith. However, about 30% felt disadvantaged due to their age. Comments revealed not a single case in which latter disadvantages were based on prejudice. Instead, ETH-wide or national age and time-based restrictions for certain positions caused the inequality perceptions. Furthermore, comments indicated that these restrictions can disadvantage scientists taking care of children. Some participants suggested a revision or removal of corresponding rules. Further suggestions included an improved availability of childcare places. ETH Zurich recently undertook great efforts to provide excellent and affordable childcare services, increasing the number of available places by about 30% in the year following this survey.