Today's Medical Fact
Our eyes never grow, and our nose and ears never stop growing.
British regulators at the Human Fertilization and Embryology Authority have approved two proposals that would allow scientists to create human-animal embryos for stem cell research. Scientists are pursuing embryonic stem cell research in order to find effective treatments for diseases such as Parkinson’s and Alzheimer’s.
These mixed cell embryos, also known as chimeras, would be 99.9 percent human and 0.1 percent animal. The embryos are being created in order to harvest them for stem cells. While many scientists cite the importance of stem cell research, many others are concerned about the ethics of mixing human cells and animal cells.
The human-animal embryos created in this research would not be allowed to develop for more than two weeks. In an odd twist, however, Bishops in the Catholic Church, who believe life begins at conception, have come out and said that women who have donated eggs should be allowed to have their babies placed in-vitro rather than killed, even though they oppose creating life solely for research.
Within the scientific community, this type of research is becoming more common. Just last year, scientists at the University of Nevada created a sheep with 85% animal cells and 15% human cells, in the pursuit of creating organs for human use. At Stanford University, researchers have created mice with brains that are 1% human, in order to study brain diseases. In 2003, Chinese scientists successfully fused human cells with rabbit eggs. Most people already accept the use of heart valves from cows and pigs for human use, which makes the recipient a human-animal chimera. For years, scientists have added human genes to bacteria and farm animals.
While the biological creation of chimeras is no longer just another science fiction story, the United States does not yet have federal laws in place that address these issues. You can expect there to be quite a debate about how to establish a reasonable balance between research and ethics in science.