Genetic enhancement, human extinction, and the best interests of posthumanity Rueda Etxebarria, Jon Genetic enhancement Human extinction Longtermism Posthumanity Transhumanism The cumulative impact of enhancement technologies may alter the human species in the very long‐term future. In this article, I will start showing how radical genetic enhancements may accelerate the conversion into a novel species. I will also clarify the concepts of ‘biological species’, ‘transhuman’ and ‘posthuman’. Then, I will summarize some ethical arguments for creating a transhuman or posthuman species with a substantially higher level of well‐being than the human one. In particular, I will present what I shall call the Principle of the Best Interests of Posthumanity, which states that the enhancement of the human and transhuman species must be directed towards the creation of a posthuman existence that is substantially more valuable than its predecessors. I suggestthathuman extinction maybe considered, within that principle, as one of the best interests of posthumanity. Finally, I will develop three objections that make that principle unattractive and that show that pursuing a full‐blown programme of posthuman evolution is ethically flawed. 2022-09-23T06:41:44Z 2022-09-23T06:41:44Z 2022-09-22 journal article Rueda, J. (2022). Genetic Enhancement, Human Extinction, and the Best Interests of Posthumanity. Bioethics. https://doi.org/10.1111/bioe.13085 https://hdl.handle.net/10481/76881 https://doi.org/10.1111/bioe.13085 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional