We don't know yet what the risks and benefits of mitochondrial replacement will be. But in a way, we're already designing babies, and medical technology will only allow us to do it to an increasing degree of precision. As the lawyer Nita Farahany put it during a recent panel during the Aspen Ideas Festival, which is organized jointly by the Aspen Institute and The Atlantic, there are now countless ways that parents are crafting their ideal children, either through natural selection or biotech.
"Who we choose as a potential mate—that's selection bias," Farahany said. "People who have abortions based on particular types of birth defects or birth anomalies. You can do full genomic sequencing. You can also select sperm donors based on traits that you find attractive."
Farahany, who also directs the Institute for Genome Sciences and Policy, said that on her fourth date with her husband, the two sat down over a glass of wine and compared "23 and Me" genetic profiles so they could better understand their compatibility at a microscopic level.
We're moving closer to the point at which people will be able to shop for specific traits for their offspring—say, blonde hair or blue eyes, to get totally eugenic on you.
Farahany seemed generally supportive of the idea on a lesser scale.
"People should be able to make a vast array of choices," she said. "It's unlikely to lead to state-sponsored eugenics, because private choices by private individuals are going to vary."
"It's not always the case that what some of us would think of as advancement is what other communities would think of as advancement, whether it's height or deafness," she added.
But others say we risk watering down the diversity of the human race. What happens when everyone wants a little Tim Tebow or Steve Jobs?
At the Aspen conference, biotech expert Marcy Darnovsky said the more we infuse science into baby-making, the closer we get to becoming a Gattaca-like dystopia, in which an upper crust of genetically superior beings dominates a vast underclass of "flawed" people whose parents couldn't afford the right types of DNA tinkering.
As the sociologist Charis Thompson told Alexis Madrigal recently:
“You start out offering these prenatal screenings for certain conditions that everybody agrees are very severe. It is not particularly eugenic, but about alleviating the suffering of the child and the parents. But there is slippage. The more you can test for and screen out, the more people do. And the example this person gave was the high number of people who will abort a fetus that is found to have an extra digit.”
With some genetic traits, though, we're already there: The number of live births to children with Down syndrome is declining because 92 percent of all women who receive a prenatal diagnosis of Down syndrome choose to abort.
In other words, we're no longer arguing about whether we design babies; we're arguing over how specific those designs should be.