The system used by bacteria to defend against a virus attacking is the CRISPR Cas 9 system. An interesting use of a protein, enzyme, and a DNA segment that can open DNA at desired locations and cut and insert new segments of DNA. We have been discussing this for well over a year now and have discussed its potential and its risks.
Now along come researchers who instead of doing this in somatic cells do it in germline cells, thus changing the potentially maturing entity. Thus each cell has this changed gene or genes.
In a recent Nature article the authors state:
There are grave concerns regarding the ethical and safety implications 
of this research. There is also fear of the negative impact it could 
have on important work involving the use of genome-editing techniques in
 somatic (non-reproductive) cells....In our view, genome editing in human embryos using current 
technologies could have unpredictable effects on future generations. 
This makes it dangerous and ethically unacceptable. Such research could 
be exploited for non-therapeutic modifications. We are concerned that a 
public outcry about such an ethical breach could hinder a promising area
 of therapeutic development, namely making genetic changes that cannot 
be inherited. At this early stage, scientists 
should agree not to modify the DNA of human reproductive cells. Should a
 truly compelling case ever arise for the therapeutic benefit of 
germline modification, we encourage an open discussion around the 
appropriate course of action.
Now this point is well made. Germline cell changes introduce all sorts of issues. Not only is there the issue of what this new gene will do, we hardly have begun to understand gene interactions, but the issues of epigentic factors such as methylation dramatically change the risks.
Frankly I miss Michael Circhton, in this case he would have clearly shown us the mistakes we could be making with an unruly unleashing of this technology. Jurassic Park would be a walk in the park as compared to what these could unleash. Imagine correcting those few genes in Apes and the other close to man mammals and see what we could get! 
The again you do have the advocates in Technology Review, that somewhat unidentifiable magazine sent to MIT alumni and others, that states:
When I visited the lab last June, ... proposed that I speak to a 
young postdoctoral scientist named ..., a Harvard recruit from 
Beijing who’d been a key player in developing a new, powerful technology
 for editing DNA, called CRISPR-Cas9. With ..., ...had founded a 
small company to engineer the genomes of pigs and cattle, sliding in 
beneficial genes and editing away bad ones. As I listened to ..., I waited for a chance to ask my real 
questions: Can any of this be done to human beings? Can we improve the 
human gene pool? The position of much of mainstream science has been 
that such meddling would be unsafe, irresponsible, and even impossible. 
But ... didn’t hesitate. Yes, of course, she said. In fact, the Harvard
 laboratory had a project to determine how it could be achieved. She 
flipped open her laptop to a PowerPoint slide titled “Germline Editing 
Meeting.” Here it was: a technical proposal to alter human heredity. “Germ line” is biologists’ jargon for the egg and sperm, which 
combine to form an embryo. By editing the DNA of these cells or the 
embryo itself, it could be possible to correct disease genes and to pass
 those genetic fixes on to future generations. Such a technology could 
be used to rid families of scourges like cystic fibrosis. It might also 
be possible to install genes that offer lifelong protection against 
infection, Alzheimer’s, and, ... told me, maybe the effects of aging. 
These would be history-making medical advances that could be as 
important to this century as vaccines were to the last.
 The problem is as the writers in Nature and in Science, led by David Baltimore, have noted, the germ line modifications could be unwieldy. 
Just because we have a new technology is no reason to let is loose. The problem with this technology is that it not only can be weaponized but that it can be done in a basement lab. This not building a nuclear weapon. This is potentially setting the world afire.
The again there is the issue of Government regulation. In an interesting piece in Xconomy the author remarks:
But researchers’ and investors’ fear that a patchwork of regulation 
would cripple biotechnology in the United States did not disappear right
 away. Biologist Thomas Maniatis of Harvard left his home lab to work on
 the techniques in tighter-security conditions at Cold Spring Harbor 
Laboratory in New York. Others went abroad. Biogen, founded in 1978, put
 its first major lab in Geneva, Switzerland. This was a time of intense concern about environmental dangers from 
the chemical industry in particular and science in general. It took some
 years for biologists to gain respect among local state, and federal 
officials for their sense of responsibility in the recombinant DNA 
maelstrom of the mid-1970s. But politicians did accept that 
biotechnology was a significant new industry that other countries, like 
Japan, might seize if America dropped the ball.
A valid point, but in the 70s we worried about errant scientists. Now we are terrified about terrorist post docs! One wonders what would be worse; the Government Regulators or the Terrorist?
