A team of scientists in Japan have recently discovered how to create female clones of male mice. Previously, animal cloning would produce offspring of the same sex as the donor cells, which limits attempts to use cloning to revive species nearing extinction (due to imbalanced sex ratios that are not ideal for reproduction). The team discovered that by using a CRISPR based method they could remove the Y chromosome to make the clones female despite originating from male mouse donor cells.
However, the team’s study cautions that this technique may not work successfully with other species of animals. Implicitly, the study suggests that there are potential conservation benefits that may emerge from this discovery. This new research has not yet been peer reviewed.
Citation:
Initiating mammalian reproduction from a single male genome
Shogo Matoba, Nonoko Umeda, Mizuki Sakamoto, Sota Komatsubara, Dinh Quoc Pham, Asako Okamoto, Aoi Ito, Takumi Ando, Hirosuke Shiura, Kimiko Inoue, Atsuo Ogura, Toshiaki Hino, Takashi Ishiuchi
bioRxiv 2026.08.03.742506; doi: Initiating mammalian reproduction from a single male genome | bioRxiv
Ethical analysis:
The concept of natural law as a basis for ethics has played a significant role in how societies have developed human rights based political systems. The modern concept of human rights has its origins in the concept of “natural rights,” which is itself rooted in natural law ethical traditions. However, the concept of natural law can also be understood as applying to all of nature, and not only to humans. A compelling argument can be made for a “natural law” responsibility to respect all the properties of nature that are beneficial for the flourishing of life on earth. These properties include but are not limited to the chemical composition of the atmosphere, the global freshwater supply, soil quality, biodiversity, and genetic diversity. Ultimately, the subtle ecological balance of living and non-living matter has many core properties that are the foundation for life thriving within our planet. Biodiversity and genetic diversity are two of the most important foundations for earth to remain a thriving biosphere.
Although cloning may help with preserving biodiversity by preventing certain species from becoming extinct, it is also a potential threat to the genetic diversity of our planet because it creates genetically identical offspring. Is it ethical to preserve a species from extinction only to condemn that species to a life of suffering and poor health due to a lack of genetic diversity? From an ethical perspective, we must consider the big picture of the well-being of endangered species rather than merely analyzing their survival from extinction.
Furthermore, it is not hard to imagine that a disease may come along and eliminate any species that are not genetically diverse enough to survive its devastation. Ultimately, we need science that can address the root cause of the problem of declining biodiversity and ecological destruction, which is wasteful agricultural and development techniques that need to be revolutionized by scientific innovation so that humans can thrive while also leaving behind a smaller ecological impact.