The EU-funded RUMIGEN project will engage with a variety of stakeholders to develop more sustainable breeding programmes and linked technologies in line with social demand, adding a novel, societal dimension defined as 'room of acceptance'. The initiative will bring together leaders in ruminant breeding from across Europe to assess adaptation to environmental stressors, such as heat stress. This work will rely on large-scale data from commercial farms combined with climatic data, involving half-sister cows raised in contrasting conditions in Denmark and India. Diversity will also be studied using new breed genome assemblies. Overall, RUMIGEN will develop models to answer questions concerning genome editing specificity and safety issues, assessing its potential to preserve genetic diversity and increase genetic gains.