The Human Fertilisation and Embryology Authority (HFEA), a governmental regulatory agency in the United Kingdom, has just approved a technique that prevents women with mitochondrial DNA disease from transmitting the faulty DNA to their children.
First, some background. Mitochondria are the cell's chief source of energy. Mitochondrial disease is a group of disorders caused by dysfunctional mitochondria, the organelles that generate energy for the cell.
Two different procedures involve the use of healthy mitochondria from a donor egg, which means that genetic material from two women is used to create an embryo free of mitochondrial disease. As reported in The Guardian, "Both procedures have been tested in animals and resulted in healthy offspring. Good results have also been seen in human cells, but treated embryos have not been implanted into a woman to achieve a pregnancy."
The approval of this innovative procedure means that its use will be the "first in humans," a situation that understandably raises concerns about safety. As is true of any biomedical intervention, unknown risks may emerge in the future, even when scientific evidence so far indicates that risks are minimal or nonexistent. However, the HFEA is a cautious regulatory body that relies on robust scientific evidence before approving new techniques in medically assisted reproduction.
If safety concerns can be laid to rest, what other ethical objections have been raised about the use of this technique? And is any of those objections ethically persuasive? First, there are the misleading catchphrases that make good headlines: "'Three-Parent' Babies Explained: What Are the Concerns and Are They Justified?" (headline in The Guardian) and "MPs Say Yes to Three-Person Babies" (BBC News).
The BBC News said: "The UK is now set to become the first country to introduce laws to allow the creation of babies from three people." But the creation of babies from three people has already been around for several decades. When an infertile couple hires a gestational surrogate to carry an embryo created by in vitro fertilization, using eggs from the woman and sperm from the man, two people contribute genetic material and a third -- the surrogate -- provides the intrauterine environment.
True, the surrogate does not contribute her genetic material, but the intrauterine environment is important for the health of the resulting baby. In these arrangements, the behavior of surrogates during pregnancy has numerous restrictions, including prohibiting consumption of tobacco and alcohol.
Some people voice ethical objections to the use of surrogates, but those objections are typically based on concerns about exploitation (wealthier women exploiting poorer women), or a birth mother having to relinquish a baby she may have bonded with during pregnancy. In these cases there are two mothers: the birth mother (the surrogate) and the genetic mother (the woman in the contracting couple). Statutes or court actions determine which mother will raise the child. (There may even be a third mother -- the rearing mother -- if the couple decides to give up the child for adoption.) According to The Guardian, in the case of mitochondria, "women who donate their mitochondria would remain anonymous and have no rights over the child."
Just how much genetic material is in the mitochondria contributed by the third person in this new procedure? Dr. Gillian Lockwood, a U.K. infertility specialist, was quoted by the BBC as saying: "The biggest problem is that this has been described as three-parent IVF. In fact it is 2.001-parent IVF. Less than a tenth of one per cent of the genome is actually going to be affected. It is not part of what makes us genetically who we are. It doesn't affect height, eye colour, intelligence, musicality."
But this brings us to another objection, pointing to the future. Even if this new procedure doesn't make us "genetically who we are," some people worry that it's the first step down a slippery slope toward creating "designer babies." Dire predictions about a dark future that will permit all sorts of things that are currently forbidden are typical responses when new technologies are introduced. But slippery-slope arguments can be countered with the reminder that one can always stop a slide down a path by instituting laws, regulations or ethically sound rules for good clinical practice.
Opponents express still another concern about the future: this genetic alteration is in the germ line, so it will be passed down through generations in families in which a woman's diseased mitochondria are replaced with healthy mitochondria. It is difficult to see how that could be an ethically persuasive objection. If the replacement procedure is not done, mitochondrial disease will be passed down through generations in affected families. It's not hard to judge which of these generational scenarios is the better alternative.
The U.S. does not have a regulatory authority like the U.K.'s HFEA that oversees medically assisted reproduction. Over the years there have been calls for creating such a body, yet those calls have not been heeded. It would be far better to have a regulatory body that is committed to rigorous scientific scrutiny than to leave such matters in the hands of politicians who pass legislation. We are all too familiar with the antiscience bias of many members of Congress. We may be better off in the U.S. with the current laissez-faire system in medically assisted reproduction than with legislation that could restrict the rights of couples wishing to avoid transmitting a heritable disease.
CORRECTION: In a blog post published on February 17, 2015, reporting on developments in the UK regarding the transmission of mitochondrial DNA disease, I mistakenly wrote that the Human Fertilisation and Embryology Authority (HFEA) had approved use of a technique to avoid transmission from an affected woman to her offspring. The HFEA does not have the authority to approve new techniques in medically assisted reproduction. That authority lies with Parliament, and requires that both houses of Parliament vote approval. At the time the blog post was published, only the House of Commons had approved the procedure; still pending is approval from the House of Lords.