In the present work, the possible influence of biology textbooks on the bioethics training of high school students in Spain has been investigated. The bioethical content of the third and fourth year of high school books of the Anaya, Santillana, Oxford and SM publishers has been reviewed, concluding that they do not guarantee the essential training in bioethics of students, nor do they allow the development of a critical spirit in the face of the enormous possibilities opened up by the advances in science. None of the books explain that biology provides objective knowledge about the beginning of life of each human being. No publisher clarifies the biological status of the embryo, thus closing the door to its recognition as a person and to reflection on the treatment it deserves, and all of them evade the concept of dignity. Only in the fourth year of high school is something about bioethics explained in two publishing houses: in the SM publishing house from a Bioethics of Principles that is not reasoned and in Anaya from a positivist and utilitarian perspective. It would be desirable to incorporate aspects of Bioethics in successive editions of Biology books in high school that would allow biology to be connected with other branches of knowledge, which favor a comprehensive development of students and prepare them for the great challenges presented by advances in biotechnology. The four editorials analysed address biotechnological issues of great bioethical significance such as the use of stem cells, cloning, artificial human reproduction and genetic editing. However, we conclude that the analysis is carried out at an aseptic level without resorting to ethical foundations and referring only to the legal limitations of these practices. Although the different texts offer topics for bioethical debate within the classroom, we highlight the absence of ethical training to be able to determine when the dignity of human life is violated.