 During the 2015 conference of the American Society of Human Genetics, his team presented findings on potential epigenetic differences in identical male twins discordant in sexual orientation.Researchers, however, noted and criticized the small sample size and questioned the statistical power of the study.Since 2014, Vilain has led the joint research unit between the French Centre National de la Recherche Scientifique (CNRS) called EpiDaPo (Epigenetics, Data, Politics), an interdisciplinary research unit which studies the societal effects of genetics, environment, and big data research.