Many "groundbreaking" news of recent times in matters of biotechnology with humans turned out to be false in the end. The current news still has us within that uncertainty. In any case, it is still surprising to see the light-heartedness of some Chinese scientists in applying the latest biotechnology to humans. The application of the CRISPR-Cas9 technique to embryos to make them immune to human immunodeficiency virus infection is yet another sample .

Although not very formalized legally in China, the ethical rules of research in human beings are clear. The procedure used must provide some benefit to the subject of research; in this case, healthy embryos that did not require any curative action were manipulated. The risks to which the subjects are subjected must be reasonably contrasted by prior experimentation on animals; but in animals, so far, the technique has not been optimized to avoid possible side effects. Also, the consent of the subject of research, in this case the parents, is required. The completed forms are apparently available at network : this is probably the only ethical requirement that has been met.

Cases such as the present one occur when technology departs from medicine and assumes a dynamism of its own, which does not take into account the subjects to which it is applied. It is true that one of the professional obligations of physicians is the technical skill and to be up to date with everything that can help a patient. But that is very different from applying techniques of unproven efficacy and safety. The latter can be done in extreme cases, as a life or death solution, a very different matter from the present one. In this case, a technical imperative has been imposed: if I have a new intervention system, it seems that I am obliged to put it into action, regardless of other considerations.

In fact, manipulation Genetics has undergone an enormous advance with the CRISPR-Cas9 technique. Before, we inserted genes in a basically random way, as if a bookbinder, in order to insert a page in a book and thus correct a typo, threw 500 books and 2000 pages out of the window and then went to the street to see which one came out right. Now, this technique allows us to "connect" the piece we want to insert with the right place, which is cut and replaced. However, it is not perfect: although the ideal is to act only on the desired place, erroneous insertions are still seen, despite being much less frequent than before.

This is not a mere technical detail: insertion in the wrong place can be biologically active (the inserted thing works well), but at the cost of irreversibly damaging the wrong place where it has been inserted. It is worth mentioning that our knowledge of the human Genetics still has a long way to go: although we know how an individual gene acts, the web of interactions between the various genes is still obscure, due to its complexity. Probably, an erroneous insertion will produce regulatory failures (think of tumors). The Genetics is more complex than the schematic version of the teaching average .

In any case, prudence, which is not shyness in the face of technical advances, calls for another subject of conduct. It requires taking into account all the known extremes of the matter at hand. And we know quite a lot about them. Specifically, our forty years of experience in in vitro fertilization have allowed us to know the side effects that manipulations of the embryo produce in children. Thus, hormonal stimulation of the woman significantly increases the health risks of the children to come; performing in vitro fertilization instead of natural fertilization also increases them; injecting the sperm into the egg instead of a natural union between the two also increases them. If we add to all this the manipulation to incorporate the gene we wish to introduce, the children could suffer from other unforeseen diseases.

In sum, if this intervention has actually occurred, it is clearly unnecessary, has treated the experimental subjects as pure research material, and is technically premature and therefore dangerous.