Published October 26, 2012
One baby, three parents. It’s a concept that sounds like science fiction, but the possibility of a child being conceived by more than two individuals is becoming more of a reality.
According to a recent report in Nature, scientists from Oregon Health & Sciences University have successfully created human embryos with genetic information from one man and two different women. The ground-breaking technique is meant to prevent the passing on of deadly mitochondrial diseases from mother to child.
Mitochondrial diseases occur when the mitochondria – small structures within cells responsible for producing energy – fail to function as they should. The result can be debilitating diseases from cell death and whole biological system failure. Because mitochondria are essential for energy production, people who suffer from these diseases typically have problems with organs in high need of energy – such as the brain, liver, heart and more.
Mitochondrial diseases can range anywhere from mild and non-threatening to incapacitating and fatal.
If the process is implemented, three-parent IVF is ultimately meant to diminish the incidence of mitochondrial diseases to as close to zero as possible. However, while the reason for the procedure seems noble, there has already been intense debate in Britain (where similar research has been done) over whether or not such conception methods are ethical. Many bioethicists are commenting that just because the procedure can be done, doesn’t necessarily mean it should.
Shaping your future child?
A child typically inherits mitochondrial disease from his or her mother – who is often a carrier for the disease and passes along her mutated mitochondria. The three-parent IVF process would potentially bypass this problem by allowing for a woman to pass along her own nucleus DNA but not her mitochondrial DNA.
With the help of another female donor, the nucleus of the donor’s egg would be removed and then replaced with the future mother’s nucleus. That way, the eggs would still have the mom’s nucleus, but contain the donor’s healthy mitochondrial DNA instead. Then the hybrid egg would be fertilized with the father’s sperm and re-implanted in the mother’s womb.
A heavily cited concern regarding this process has been whether or not the procedure is the first step towards “designer babies” – a theme explored in the 1997 science fiction film Gattaca, in which parents were able to select the most desirable genes for their future child to possess. But according to one bioethicist, the term that people should really be using to describe this technique is something even more poignant – cloning.
“It uses the same principle as cloning, switching out the DNA of one women for the DNA of another,” Laurie Zoloth, a professor of medical humanities and bioethics at Northwestern University, told FoxNews.com. “…Last time we debated cloning, using adult cells and not eggs– we were determining whether it could be used as a method to make a matched stem cell line. It was ultimately decided you can use cloning for stem cell lines, but not to make babies because of the risks involved when you manipulate embryos this much. We’ve had the debate, and the answer has been ‘no.’ We can’t just go ahead and say the debate didn’t happen.”
According to Zoloth, the procedure is essentially using techniques utilized in the cloning process. While the scientists aren’t making an exact copy of a fertilized embryo, they do end up making a manipulated copy of an egg cell. Not only is this similar to cloning children, it can also lead to genetic defects and abnormalities that researchers have never seen before.
Because of this, Zoloth said the procedure is crossing a “bright line” of bioethics – what is known as the prohibition of germline genetic therapy. According to her, many bioethicists agree that genetic intervention can be done as long as only one person is affected – the human subject. If a person has a genetic disease, they have the right to have the disease treated, but their DNA cannot be altered in a way so that it affects the next generation (their offspring).
“The way we have avoided genetic diseases so far is by selecting embryos without the [faulty] genetic characteristics and using them to initiate a pregnancy,” Zoloth said. “We didn’t allow for manipulation of the DNA of the embryo, because we want to draw a line – against therapies that can be treated in one person and then passed on through the generations. This [study] calls out that line.”
Can mitochondrial disease be eliminated?
While the ultimate goal of three-parent IVF is to essentially eliminate mitochondrial diseases from the human population, Zoloth said that the intent is more to help mothers wanting to pass along their DNA without the devastating consequences. This is more of a prevention method than an “antidote.”
“It’s not about curing mitochondrial disease,” Zoloth said. “It’s about women who are carriers for mitochondrial disease who have perhaps had one child with a severe case and don’t want to have a second. But this doesn’t cure the disease or keep the baby from having disease. It just prevents transmission to the embryo through very high-risk technology. It makes a brand new sort of egg cell, and we have no idea what that means in humans.”
Another caveat is that not all mitochondrial diseases are caused by mutated mitochondria. In fact, more often than not, they can be triggered by mutations in parts of the nucleus that interact with the mitochondria. Therefore, three-parent IVF will have no effect on these kinds of conditions.
“If we were able to know every single mom who carried mitochondria DNA mutations, and use this technique, then we could effectively eliminate the [diseases] that come from the mitochondrial DNA,” Dr. Suzanne Debrosse, a pediatric geneticist specializing in mitochondrial diseases at University Hospitals Case Medical Center in Cleveland, Ohio, told FoxNews.com. “However, this doesn’t help with the mitochondria disorders that come from the nucleus DNA. Since the mom’s donating her nucleus, this will not help them.”
Ethical and moral questions aside, many scientists and doctors also question if this is a step forward for science. Since three-parent IVF is still in the early stages of discovery, many cannot attest to whether or not this will be a viable option for individuals. Many logistics still need to be considered – such as organization and regulation, possible payment methods for donors, screening processes and more.
When it comes to research into novel procedures, one doctor said it is important to look at the opportunity cost of moving forward.
“I’m a proponent of science, and with anything that will limit suffering, you have to explore it,” Dr. Michael Lucchesi, chief medical officer for SUNY Downstate Medical Center in Brooklyn, told FoxNews.com. “But you have to look at this ‘juice-to-squeeze’ ratio. It’s going to take a long time to do this and a long time to determine what particular mitochondrial genes you’d like to isolate. You have to think about the amount of resources you’re going to use versus the amount of benefit you’re going to get from them. And with the way finances are, there are always limited resources, and if you’re going to utilize resources for one type of experimentation, it’s going to take away resources from something else.”
For women who want the experience of pregnancy and birth, there are a number of low technology options – such as traditional IVF – as well as the option of adoption for those who simply want to be parents, Zoloth said. According to her, taking this new route is only meant to satisfy an archaic desire.
“People really want what they think is 'their' DNA,” Zoloth said. “That’s ethically problematic, because you’re taking a huge risk for this very narrow purpose – which is passing on [your] particular genetic code at a very high cost. It is saying that this genetic passing on is at such importance to me that I’m willing to risk the potential health of my child.”
With so many other options available for parents, Zoloth contended that it is almost another ethical issue not to utilize alternative parenting routes.
“In light of a world in which millions of children need good homes – half a million children are in American foster care – surely there are other ways to be a parent,” Zoloth said.