Scott's monthly roundup of interesting links covering AI policy developments, technology news, cultural observations, and scientific research from December 2025. Longer summary

This is Scott Alexander's monthly collection of links and commentary covering diverse topics. Major themes include AI policy battles (chip sales to China, regulation debates, political campaigns), startup news (Substrate fraud allegations, Tornyol mosquito drones), and scientific updates (COVID origins, Hitler's DNA, lactose intolerance). The post also covers cultural topics like the first millennial saint, Dimes Square commentary, and political polling about ideal Democratic candidates. Scott provides his characteristic mix of straightforward reporting, skeptical analysis, and occasional humor throughout the 53 linked items. Shorter summary

Scott responds to three concerns about embryo selection: embryo personhood rights, loss of trait diversity, and the ethics of preventing disabilities, arguing that none of these objections are fatal to the technology. Longer summary

Scott Alexander responds to three major concerns about embryo selection raised in response to a previous post. First, he addresses whether embryos have personhood rights, arguing that embryos lack the qualities (consciousness, intelligence, etc) that make humans morally valuable. He refutes various counterarguments about potential personhood and responds to edge cases like sleeping hermits. Second, he discusses concerns about trait diversity, arguing that the technology's limited power and slow adoption mean diversity concerns are premature. Third, he addresses the ethics of telling disabled people you'd prefer they didn't exist, comparing it to other situations where we try to prevent certain conditions without devaluing existing people. Shorter summary

Scott analyzes the sudden emergence of commercial trait-based embryo selection services, discussing both the scientific validity and ethical implications of selecting embryos for health outcomes, intelligence, and physical traits. Longer summary

Scott examines the recent development of commercial embryo selection services, particularly focusing on companies like Genomic Prediction, Orchid Health, Nucleus, and Herasight. He explains how the technology works, comparing different companies' claims and methodologies, and discusses both scientific challenges and ethical concerns. The post explores the potential benefits, like reduced disease risk and increased IQ, while acknowledging issues around cost, racial disparities, and social implications. A significant portion focuses on Herasight's critique of competitor Nucleus's scientific claims. The post concludes by placing this technology in the broader context of human enhancement and future technological developments. Shorter summary

Scott Alexander argues that using polygenic screening to select low-risk embryos can be considered as preventing genetic disorders, drawing parallels with other accepted preventive practices. Longer summary

Scott Alexander discusses the ethical implications of using polygenic screening to select embryos with lower risk of genetic disorders, specifically schizophrenia. He argues that this practice can be considered as prevention of the disorder, despite objections that it's merely replacing a high-risk individual with a low-risk one. To support his argument, Scott presents three analogous situations: preventing fetal alcohol syndrome, selecting embryos in IVF, and preventing child abuse through parenting workshops. He concludes that polygenic selection is ethically comparable to these widely accepted practices and can be fairly described as preventing schizophrenia. Shorter summary

Scott Alexander examines obscure pregnancy interventions that may improve child outcomes, rating them by evidence quality and potential impact. Longer summary

Scott Alexander reviews various obscure pregnancy interventions that could potentially improve child outcomes, particularly IQ. He rates them in tiers based on evidence strength and potential impact, with Tier 1 being most strongly supported. Key interventions discussed include embryo selection, choline supplementation, avoiding stress and certain substances, and optimizing birth timing. He emphasizes these are extreme measures not meant to induce guilt, and that standard pregnancy advice is still most important. Shorter summary

Scott Alexander discusses the birth of the first polygenically-screened baby and explores the current and potential future applications of this technology in IVF. Longer summary

Scott Alexander discusses the birth of the first polygenically-screened baby, explaining the process of in vitro fertilization (IVF) and how polygenic screening works. He describes how this technology can be used to reduce the risk of genetic diseases and potentially select for other traits. The post covers the current capabilities of polygenic screening, its potential future applications, and some ethical considerations. Scott also mentions the first polygenically screened baby, named Aurea, born to a family with a history of breast cancer. Shorter summary