CRISPR, a remarkably effective biological tool for genetic engineering, recently allowed scientists to remove a malfunctioning gene from a human embryo in a landmark procedure. This success subsequently implies all sorts of future possibilities for trait selection and deletion, but once this procedure is perfected (theoretically) in the future, and all genetic diseases are cured, how far will it take us toward so-called “designer babies”? Are we, like John from Brave New World or Vincent from Gattaca, about to head into a society sharply divided by the altered quality of our genomes, or will we forever be able to achieve fates not determined solely by our biological blueprints?

To answer these questions, we first need to understand how CRISPR, or Clustered Regularly Interspaced Short Palindromic Repeats, works, and what the process is capable of achieving. The biological phenomenon, which was first identified by researchers in Japan in the ’80s, is actually a bacterium’s defense system against bacteriophages (viruses that attack bacteria). It turns out that this defense system can be inserted into other types of cells, and repurposed to select specific genes from a given genome—human or other—and either cut them out completely, or delete them and replace them with substitute genes.

The bacterium’s defense system can be repurposed in this fashion because it basically operates by taking the genes of invading bacteriophages, duplicating those genes, inserting them into the genome as “spacers” between repeating genes (hence “Palindromic Repeats”) and then telling RNA (or “messenger RNA” because it does the bidding of DNA in the cell) to find any DNA that matches the recorded spacers, and destroy it. In the case of purposefully engineering a genome, instead of deleting the genes of invading bacteriophages, a specific unwanted gene is made “the enemy” and destroyed.

But you may be saying to yourself: I’ve heard of lots of genetic engineering breakthroughs before, what makes CRISPR—and particularly this success with the removal of a defunct gene from a human embryo—so special? Well, what makes CRISPR such a breakthrough technology is the exactitude with which it locates and deletes specific genes. Right now, doctors can alter DNA with the use of radiation therapy (in an effort to destroy cancer cells, for example), or they can use gene therapy that uses viral vectors to deliver DNA into target cells. But both of those methods are relatively scattershot, as radiation harms healthy cells as well as cancerous ones, and viral vectors can target the wrong cells for DNA insertion. But CRISPR is far more targeted, as scientists can program CRISPR genes, as well as Cas9 (an RNA-guided enzyme that obeys the orders of the CRISPR genes) to target a single specific gene and have it wiped out.

Cas9 selecting and removing an invading bacteriophage’s genes. This is the same process used to delete unwanted genes in the human genome. Image: YouTube / MIT

This is exactly what researchers, led by Shoukhrat Mitalipov of Oregon Health and Science University, were able to achieve recently inside of a human embryo. In their paper published in the journal Nature, Mitalipov and the rest of the team describe how they were able to use CRISPR to clip a malfunctioning MYBPC3 gene—responsible for making cardiac proteins—from an embryo’s DNA. And while CRISPR has been used by Chinese researchers to treat a human before, meaning this isn’t the first human experiment, this is the first time that an embryo has been altered using CRISPR without any apparent issues arising.

While this experiment was only a trial run (the genetically altered embryos are going to be discarded), it does seem to stand as an adequate proof-of-concept for CRISPR working as a tool for accurately modifying an embryo’s genome. Which takes us to our question: When we gettin’ those babies as athletic as Wonder Woman and as brilliant as Tony Stark poppin’ off the line?

That issue is obviously still up for debate. Essentially, scientists who claim that CRISPR will never be able to consistently create super geniuses or super athletes make their argument on the grounds of what amounts to genetic whack-a-mole. That is, “fixing” one gene in one part of the genome may cause an issue with another gene somewhere else in the genome. And aside from that, unlike the MYBPC3 gene that was removed from human embryos in this most recent procedure, traits like intelligence are affected by multiple genes. It’s going to be far more difficult to determine which genes, in which combinations, are responsible for broad traits.

On top of that, the argument has been made that regardless of how good CRISPR becomes, there will always be the issue of nature vs. nurture. That is to say, even if you could engineer an embryo to have a “perfect” genome, it still may not be expressed perfectly due to environmental factors. For example, even if you give an embryo the exact same genes as Michael Phelps, if all he does as he’s growing up is sit on the couch and eat Doritos, he’s not going to be any kind of world-class athlete (except for maybe esports?). In other words, the genome for exceptional performance may be present inside a person’s cells, but the environment may not allow the expression of said DNA. That interplay between nature and nurture is known as epigenetics, and it’s responsible for who we are just as much as our genomes.

But what if we do manage to figure out which sets of genes are responsible for general traits like intelligence or charm or grace or even talent? Then you get into what Elon Musk calls “The Hitler Problem.” When asked about why he hadn’t gotten into genetic engineering, Musk responded: “Hitler was all about creating the Ãœbermensch and genetic purity, and it’s like— how do you avoid [that]?”

If Musk believes there’s no way to avoid that problem, then it’s probably worth some serious consideration for the rest of us. Worlds like the ones in Gattaca or Brave New World are not exactly utopian, although as Vincent notes, “there’s no gene for fate.”

What do you think about CRISPR and the possibility of designer babies? Let us know your thoughts in the comments below!

Images: Columbia Pictures