February 3, 2017
(The Conversation UK) – The chimeric pig foetuses produced by Juan Izpisua Belmonte, Jun Wu and their team at the Salk Institute were not allowed to develop to term, and contained human cells in multiple tissues. The actual proportion of human cells in the chimeras was quite low and their presence appeared to interfere with development. Even so, the study represents a first step in a new avenue of stem cell research which has great promise. But it also raises serious ethical concerns.