A couple of weeks ago, the British government gave tentative approval to Britain's Human Fertilization and Embryology Authority (HFEA) to review scientific licenses to create "cybrids," or hybridized human-animal embryos, for stem cell research. Cybrids, also known as cytoplastic hybrids, are created by injecting a human nucleus into an animal egg emptied of its own nucleus.
Scientists say this interspecies somatic cell nuclear transfer technique, and the cybrids that result, would dramatically increase the dwindling supply of stem cells needed to study degenerative disease. They also say the cybrids mimic human embryos to an astounding degree. In fact, since their DNA is 100 percent human, their totality would be 99.9 percent human and 0.1 percent animal, sort of like a person dressed in head-to-toe suede.
As Dr. Stephen Minger of Kings College London, one of the applicants for a cytoplastic hybrid embryo license put it, "What we do when we take an animal egg, is we remove the nucleus from the egg. We remove not only the genetic identity but we remove the species identity. What makes a cow egg a cow is its nuclear DNA. And we take that out -- it's no longer a cow."
Opponents argue that mixing even the tiniest amounts of human and animal genetic material is unnatural and wrong. Scientific advance and potential strides toward a cure for Alzheimer's or Parkinson's aside, they worry that interspecies genetic concoctions overstep acceptable ethical boundaries. They envision the technique, and the resulting embryo mutts, as entrée into the land of chimeras, organisms composed of cells from two or more animals. They worry it will inevitably lead to dangerous experimentation with growing new sorts of creatures, whether human or animal or something in between. So far, the only animals on the laboratory menu are cows and rabbits, so the Frankenstein scenarios have centered around "cowumans" and "humabbits."
But there is absolutely no evidence that scientists are interested in creating "true hybrids," those made by fusing a human sperm and an animal egg, or "human chimeras," in which human cells are injected into animal embryos. The HFEA has not yet made a decision on these techniques, and there is no cause to assume researchers are interested in anything other than regular old stem cell research, the sort of research that holds such promise in finding cures to excruciating diseases.
In his 2006 State of the Union address, President Bush called "human-animal embryos" one of "the most egregious abuses of medical research." In fact, Bush supported legislation to imprison scientists for creating cellular chimeras. But chimeras have been an indispensable scientific tool for decades. In 1988, for example, scientists used mice with human immune systems to prove that HIV causes AIDS.
There are several reasons to applaud Britain's first steps and to permit this sort of research here in the U.S. Putting aside the sheer importance of scientific advancement and reestablishing the United States as a leader in the field, research using cybrids is not the slide down the slippery slope that concern religious leaders and Bush.
First, the differences between humans and animals are such that it would be nearly impossible for anybody, even the most atheistic and monomaniacal mad scientist, to actually concoct man-bunnies. Second, there is no animal nuclear DNA involved, restricting the animal function to mere casing for the human ingredients within. The HFEA also specifies that licensees adhere to strict regulations and promises intense oversight. For example, cybrids would have to be destroyed after 14 days development, which gives the scientists enough time to extract stem cells but ensures that growth would stop before they could develop into anything even remotely fetal. In addition, the cybrids wouldn't be transferred into any uterus, whether human or bovine, volunteered or not.
Finally, as part of the initial approval, the British government questioned 2,000 people, gauging their opinions on the ethics of human-animal embryos. The survey found that a majority, 61 percent, support the research if the hybrids promise insight into diseases. This is significant, for we, all of us, are our own best moral watchdogs. We hurt ourselves and our own futures -- spiritual and physical -- if we allow fear about abstract potentials get in the way of scientific advancement and potential medical benefit.
I realize, of course, that it is the human component of cybrids that is the greatest cause for concern, the fact we're talking not about mixing dog breeds to come up with something fluffy and hypoallergenic, but about mixing species, our own among them. But researchers seeking to use cybrids do not intend to develop new and improved pets or people. Rather, they're seeking cures for those that are already around.