Experiments combining human and pig cells provoke strong responses from some people, but is the reaction justified.

For the millions of diminutive fans of Peppa Pig there is almost nothing cuter than a talking piglet. Outside cartoon land the boundary between pig and human is also blurring; and the response, in some quarters, is less enthusiastic.

In January 2017 a team led by Juan Carlos Izpisua Belmonte, at the Salk Institute in California, announced it had introduced human stem cells into pig embryos. The result was a hybrid embryo, part pig, part human. Such creations are called chimeras, after the mythological creature that blended lion, goat and snake.

No Peppa Pig resulted. Just one in 100,000 of the embryo cells were human, and the embryos were destroyed after 28 days. The researchers’ stated goal was to test which types of human stem cells would best engraft into a pig embryo, with the ultimate aim of directing those cells to grow into human organs that might, one day, be used for transplants.

Nonetheless, such experiments often elicit a repugnance that can morph rapidly into moral condemnation.

Read the full article in Cosmos magazine here