Ethical testing rodents were genetically engineered by splicing human DNA with that of a rat. ETRs are nearly human, over 99.9% genetically identical to humans, their white lab rat-like appearance is purely to make scientists more comfortable with using them to test products.

Since their creation, they have largely replaced traditional lab rats in testing products for chemical hazards to humans.

Despite being the product of genetic engineering, ETRs are not cloned or vat-grown, they're birthed live from female ETRs who are naturally inseminated and give natural births, to promote the same genetic diversity found in humans.

Though their purpose in life isn't glamorous, companies who purchase ETRs for use in testing are given a number of guidelines for their proper housing and care, so that their sometimes short and often painful lives can at least be someqhat comfortable, ranging from simple comfortable quarters to something as complicated as an artificial biome, though some companies with a deeper appreciation for money than life have opted for small concrete cells with cage doors.

ETRs are a secret well kept from the world at large. The public benefits from safer products, and is better off not knowing why the margin of quality has increased so significantly.