Vasiliūnaitė, E. and Giniotaitė, A. 2023. „You are either a boy or a girl – there is no other choice.“ Analysis of the Biological Sex Concept in Biology Textbooks. Acta Paedagogica Vilnensia. 50, (Aug. 2023), 107–128. DOI:https://doi.org/10.15388/ActPaed.2023.50.7.