Is it far fetched? Perhaps. Is it possible? Entirely.
It's possible because of a little thing scientists like to call a chimera. A chimera is created by mixing cells from two different species. In a simplified version of the scenario above, you could inject human stem cells into some mice embryos and let the resulting mice be born. You are bound to get some mice born eventually that have human reproductive cells. Just mate a mouse with human sperm and a mouse with human eggs and you have a 100% human baby. Of course, the embryo would have to be implanted in a human womb, but that is a routine procedure now. Which brings me to a fascinating debate going on in England.
The British Parliament is considering allowing scientists to create chimeric embryos as long as they are destroyed after two weeks. They say it will be against the law to implant these embryos. The problem is The Catholic bishops have come out and said if these chimeric embryos are created, they have a right to life. They don't think they should be made at all, but if scientists do go ahead with it, then they should be allowed to live. Specifically, this is what the Bishop's say:
"It should not be a crime to transfer them, or other human embryos, to the body of the woman providing the ovum, in cases where a human ovum has been used to create them. ... Such a woman is the genetic mother, or partial mother, of the embryo; should she have a change of heart and wish to carry her child to term, she should not be prevented from doing so.”
Can you imagine?!!
Because this is the topic of my current book, I have asked a lot of people their thoughts on a non-human animal/human hybrid creation. I can tell you that the reaction is almost always something akin to "ick" or "are you crazy?" or "god help us if that ever happens" or "step away from the tequila." Actually, by the reactions I can honestly say I think these creatures are better off not ever being born. They would be outcasts, slaves, burned on stakes in horrible rituals, tortured, ridiculed and at the very least have no rights.
Here in the U.S. we tried to pass the Human Chimera Prohibition Act back in 2005. It never became a law. What we have instead is a National Academy of Science ethics board that scientists are urged to run experiments by before they attempt anything like this. There is also only regulations put on government funded labs. Private labs can do whatever they want.
So, now I'm asking you. If scientists are allowed to create human-non-human embryos...do you think they have a right to be born? What if the creation had more than sixty percent human DNA and only forty percent mouse? Would that make a difference?