Scientists Create First Human-Pig Chimera In The Lab ★★★

Researchers hope to overcome the problem of organ shortages for transplantation by growing spare human organs in other animals.

A group led by scientists at the Salk Institute for Biological Studies has taken the first  step toward making this a reality. On January 26, 2017, they announced having grown the first human-pig chimeric embryos in the lab.

While the ultimate goal of producing organs for transplantation still seems to be in the distant future, ethical questions are still an issue. How many cells do you need for a chimera to be considered more human than pig?  Does it matter what kind of cells, what kind of tissues?