The Croatian-Slovenian bilateral multidisciplinary project ''The Role of Genetics, Biological Age, and Muscle Fiber Characteristics in Talent Development and Sports Performance: A Twin Study'' (TWINSWINS) explores how genetic, biological, and environmental factors influence the development of sports talents. The project is based on previous research that has demonstrated the need to improve the developmental processes of young athletes. Including multidisciplinary experts from kinesiology, biomedicine, biotechnology, and sociology, the project utilizes non-invasive modern technologies such as Tensiomyography (TMG), thermography, MyotonPRO digital palpation device, Muscle Talent Scan MRI measurements ,and ultrasonic assessment of bone age (SonicBone) to analyze young Croatian & Slovenian athletes, including a sample of monozygotic/dizygotic twins and their parents. The goal is to enhance diagnostic tools to enable more precise monitoring and development of young athletes. The results are expected to improve the identification and development of young athletes, providing a better understanding of the Relative Age Effect (RAE) and genetic predispositions. Scientific contributions include publishing results in prestigious journals and storing data in open databases, enabling further analysis. The project's societal benefits include improved training and selection processes, which can reduce sports injuries and dropout rates. The end-users are athletes, parents, coaches, sports academies, clubs, national sports associations, educational institutions, and sports professionals. TWINSWINS could transform the approach to training, promoting a holistic approach to the development of young athletes that considers ethics, genetics, the environment, and biological age, contributing to the scientific community and social application in sports and education.