In our daily lives, we rarely become conscious of the fact that most animals and plants that we see around us continue to be genetically modified by our own hands. We have shared our daily lives with farm animals, pets, or house plants for generations. Some of them have been biologically modified to become stronger, while others have changed their colors to appeal aesthetically to humans. The history of genetic modification is long. In the Edo period(1603 – 1868), Japanese people commonly genetically modified plants and flowers such as cherry blossoms, morning glories, chrysanthemums and camellias in pursuit of more beautiful greenery. Silkworms, along with the development of clothing materials, were another subject of genetic modification. For commercial and practical purposes, people have studied and created genetically modified silkworms that could fight illness, grow stronger, and generate more beautiful and higher-quality threads. Scientific technologies have developed further today, and we can now control genes extremely precisely. We have acquired means that allow even bigger impacts on life. While this could bring about great contributions, it also requires us to possess a high sense of ethics.