Scientists in the UK applied for permission to create part-cow, part-human embryos for research aimed at treating diseases such as Parkinson's and Alzheimer's. The embryos created from this process would then be almost entirely "human", with the only cow DNA being outside the cells' nuclei. The human-bovine embryos would not be allowed to develop for more than a few days, the researchers say.
The proposal has been questioned by some ethics campaigners, who claim it could blur the line between animals and humans.
Read more: newscientist.com