The argument that three-person in-vitro fertilization is a step toward engineering "designer babies" doesn't make sense to Lori Martin, whose 4-year-old son Will was born with an incurable genetic disease and likely won't survive past childhood.
Three-person IVF, called mitochondrial transfer, may be on its way to fruition in the United Kingdom as a means of eliminating mitochondrial diseases like Will's by swapping out the genetic material that causes it.
"I could never imagine myself trying to engineer some insanely talented kid because my first kid that I created had this terrible disease," said Martin, who lives in Houston. "It just doesn't register in my mind that way at all…They want to give another child a chance to have a healthy and happy life."
Will has a mitochondrial disease called Leigh's disease, which renders his cells unable to turn food into fuel. It's passed down from the mother via mitochondrial DNA and has no cure.
"There's no crystal ball to tell you what's going to happen tomorrow," Martin said. "He could wake up tomorrow and have lost all function. There's no rhyme or reason."
Because Will's condition is genetic, doctors told Martin she shouldn't have any more children without using a healthy egg from a donor. Although a baby from a donor egg would be free of Martin's bad mitochondrial DNA, it would also lack the 99.8 percent of her DNA that is not responsible for Will's condition but is to blame for her brown hair, her smile and all her other physical traits.
3-Person IVF 101
The mitochondria are the energy-producing parts of every cell — think of them as little batteries. As such, cells don't function properly if someone has a mitochondrial disease because cells can't turn food into fuel. For patients with Leigh's disease, for example, the mitochondria fail over time, and children often don't live past age 7.
Mitochondrial DNA determines how the mitochondria will function, but it's only passed on from the mother. Nuclear DNA comes from both parents and determines children's characteristics, such as eye color and height.
The three-person IVF being proposed in the United Kingdom would keep the nuclear DNA from both parents while swapping out the mother's "bad" mitochondrial DNA for a donor's mitochondrial DNA. Government officials estimate that it will be able to save 10 lives per year.
Why It Won't Be Available in the US Soon
But in the United States, the Food and Drug Administration effectively banned a similar procedure called cytoplasm transfer in 2001.
Therapy that involves manipulating cells beyond traditional IVF – an egg cell being fertilized by a sperm cell – falls under the FDA's jurisdiction.
According to a 2001 letter that went to clinics practicing cytoplasm transplants, which include injecting cytoplasm from a young egg into the cytoplasm of a new egg without removing any existing material, the FDA must conduct a clinical investigation, which can't even start until an "investigational new drug" application has been filed.
But that was more than a decade ago. Since then, no clinic has been approved, and the FDA is not allowed to comment on whether any applications have been filed, according to a spokesman.
"There are, of course, people who think this is inappropriate," said Debra Mathews, a bioethicist at the Berman Institute at Johns Hopkins University Medical School. "That this is the first step on the way to designer babies."
Although three-person IVF has similarities to cytoplasm transfer, the intent is different, Mathews said. Three-person IVF is not just about increasing the chances IVF will work, it's about creating a baby without a deadly disease.
"We certainly think about things differently in different contexts," Mathews said.
Options for Parents with Mitochondrial DNA Flaws
Mothers often don't know there's anything wrong with their mitochondrial DNA until they have a child with mitochondrial disease, said Dr. Mary Kay Koenig, a pediatric neurologist at the University of Texas Health Science Center at Houston. Koenig specializes in mitochondrial disease and oversees the center's Leigh's syndrome clinic, where she treats Will.
She said there are three options for parents at risk for passing on mitochondrial disease to their children: Take their chances and have another baby anyway, don't have any more children, or use an egg donor. But using an egg donor can be difficult and expensive and isn't an option for everyone, she said.
Most of Koenig's patients either opt to have no more children or take their chances. Those who take their chances often have more babies with different presentations of the same mitochondrial disease.
"I see families who have five and six siblings all affected by mitochondrial disease," she said.
To Koenig, the three-person IVF that's been proposed in the United Kingdom isn't about "designer babies."
"In my opinion, this doesn't fit in," she said. "A lot of people see that as genetic selection, but it's really about people being responsible… They're not asking us to pick a girl or a boy, blond hair or brown hair. They're just asking us to pick whether or not that child has Leigh's syndrome."
Martins Expanding Their Family
It took Martin two years, but she's finally pregnant with her second child after undergoing IVF with a donor egg. The baby won't have her genetic material, but it will have her husband's genes and no mitochondrial disease.
No one is happier than the baby's soon-to-be big brother, Will.
"If you ask him, 'Are you gonna have a baby brother or sister?' he'll very emphatically and authoritatively say 'boy' or 'brother,'" Martin said, adding that she has no idea whether the baby is a boy or a girl. "He's as excited as a 4-year-old can get about something he probably doesn't really grasp."
It isn't three-person IVF, but Martin said there's still something empowering about leaving her mitochondrial flaws behind.
"There will not be another child from our family to have this exact gene," she said. "It's kind of exciting to stop something so terrible from ever occurring again."