By Nicolás Jouve, Professor of Genetics, President of CiViCa (member of the One of Us Federation)
On February of 2015 a request formulated by the Human Fertilization and Embryology Authority (HFEA), to apply a method of obtaining three-parent human embryos (two mothers and a father), was approved by the House of Commons in the United Kingdom. The technique, developed in Newcastle, uses a modified version of in vitro fertilization to combine the healthy mitochondria of an ovum cell donned by a woman with DNA of the other two parents (ovum and sperm), as a way to avoid mitochondrial diseases transmission.
Which is persecuted with the production of the three-parent embryos is to avoid the transmission of mitochondrial altered genes of an ovum of the mother carrying a mitochondrial disease by the cytoplasm of an egg from a donor. The replacement is made by nucleus transplantation after obtaining an embryo by in vitro fertilization. It is necessary to remember that mitochondria, which have a minimum amount of DNA, are transmitted only by maternal via.
According to the promoters of this technique, the objective is not to create perfect babies, but healthy babies. Nevertheless, the bioethical question is which the price is. To change the mitochondria of an egg had been never made before now and the most disquieting of this technology is to know if this dangerous operation would have consequences for the health of the baby after being born.
The journal New Scientist announced yesterday that a child was born using this controversial technique five months ago, and this opens certain ethical questions.
The first question concerns the inevitability of repeating the manipulation of the recipient egg, the in vitro fertilization and nuclei transplantation several times until obtaining a viable embryo. This creates a great ethical problem, the elimination of human embryos, which are human lives in the initial phase of their development. It is difficult to venture the result, but the fertilization in vitro has a successful of no more than 28-30% in the laboratories in which it is carried out. On the other hand, the manipulation of the embryos provokes a great loss of human lives (ex.: the “preimplantation genetic diagnosis” gives only a 2% of viable embryos). Which would be the proportion of viable three-parent embryos? This data does not appear in the news of the birth of a three-parent baby announced in New Scientist.
Another problem is to have an important reserve of egg cells to repeat the attempts. The technique increases the demand of egg donors, with all its consequences. It is necessary to remember that the egg donors must be submitted to hormonal treatments, which implies long-term risks by the drugs used to stimulate ovulation, sometimes with very serious consequences for the health of the donors.
The next great doubt is what would be the consequences for the health of the human lives coming from this technology after the great manipulation of the three-parent embryos? Here, it is necessary to warn on a reality of the current pediatric medicine, which is the knowledge of the negative influence due to epigenetic modifications than can exert certain environmental factors, derived from the in vitro fertilization techniques. Although most of the children coming from the fertilization in vitro have a normal development, it has been demonstrated that the conditions of the embryonic manipulation can induce changes introducing epigenetic marks in certain genes which would see altered its expression during the embryonic development [1-3]. In the case of the three-parent babies the manipulation is even greater than in the simple fertilization in vitro. This is a new technology and there is not neither security nor way to know which would be the impact in the health of the babies after being born with this technology.
After all this series of doubts and inconveniences, is ethical to apply this technological adventure with so few guarantees of success and as much insecurity for the health of the babies? Who is able to guarantee the health of the babies of three-parent origin? Is ethically acceptable everything what it seems technically possible?
Finally, the technology of the three-parent babies opens a field that until now was forbidden. The genetic manipulation of an embryo is also a genetic manipulation before the development of the germ line… which implies the risk of altering the genetic information of the future generations of descendants of the three-parent babies obtained.
[1] Behr, B.,Wang. H. «Effects of culture conditions on IVF outcome», en European Journal Obstetrice Gynecology and Reproduction Biology. 115 (2004) (Suppl. 1), S72–S76.
[2] De Baun, M.R., Niemitz, E.L., Feinberg A.P. «Association of in vitro fertilization with Beckwith–Wiedemann syndrome and epigenetic alterations of LIT1and H19», en American Journal Human Genetics 72 (2003), 156–160
[3] Hansen, M., Bower, C., Milne, E., de Klerk, N., Kurinczuk, J.J. «Assisted reproductive technologies and the risk of birth defects—a systematic review». Hum Reproduction. (2005), 20: 328-338
