As the Trump administration concludes the use of animal testing within the federal government, a biotech startup is suggesting a novel alternative: nonsentient “organ sacks.” R3 Bio, located in the Bay Area, is pitching this concept to investors and industry publications as a means to substitute lab animals without ethical dilemmas. These constructs would contain all organs except a brain, rendering them incapable of cognition or experiencing pain. Cofounder Alice Gilman states the aim is to develop human equivalents for tissue and organ transplantation. Immortal Dragons, a fund based in Singapore, regards this as a longevity strategy, prioritizing replacement over repair. R3 intends to create monkey organ sacks for more ethical and scalable testing. Monkeys, which are essential yet diminishing resources for drug testing, particularly during Covid-19, are experiencing a decline in availability across the U.S. The shift toward less animal testing is driven by animal rights advocates and federal actions. Organ sacks could become essential as research monkeys become increasingly scarce, providing benefits over existing models that lack comprehensive organ complexity. Gilman mentions they can produce mouse organ sacks without a brain but refrains from confirming their creation. The company is investigating the application of stem-cell technology and gene editing to develop monkey and human organ sacks. According to Paul Knoepfler, a stem cell biologist at UC Davis, organ sacks could originate from induced pluripotent stem cells, which are reprogrammed adult skin cells capable of transforming into any type of body tissue. Scientists could inactivate brain development genes and cultivate embryos into organ structures.