Stem cell research promises a cure for the toughest and challenging diseases of today. Growing tissues and organs, however, is impossible without the embryonic material. A wast controversy evolved around this issue. Some people consider that after conception human embryos at all stages are already human beings, consequently, killing an embryo equals killing a human. Growing and using hybrid embryos became even more critical point. The mere idea that the nuclei of human cells can produce fully-fledged embryos when inserted into animal eggs sounds at least revolutionary.
In a creation of a cytoplasmic hybrid embryo both animal and human tissues are involved. In such a case, nuclei which contain human DNA are inserted into animal eggs which have all the genetic information removed. As a result, the embryos are more than 99 percent human. Due to the lack of human eggs available for stem cells research, hybrid cytoplasmic embryos are very useful as their stem cells allow to grow just any type of human tissues.
Hybrid embryos are harvested up to 14 days, and then they are destroyed. At that, scientists do not intend to create living animal-human beings or chimeras. Opponents of the creation of hybrid embryos suppose that such activity is a gross violation of the laws of nature as well as human and animal rights; furthermore, it is at odds with most religions. Creating living beings solely for scientific disposal contradicts human ethics, in their opinion. On the other hand, stem cell research is crucial for medicine and science. Researchers argue that hybrid creatures are merely cells but not humans. Besides, embryos involve neither human eggs, not human fertilization to be produced which confirms that they do not violate human rights.