What happened: Nature magazine published a scientific paper announcing an astonishing breakthrough. A team of scientists at Oregon Health & Science University in Portland were able to successfully edit the genes of human embryos.

Using a gene-splicing technology called CRISPR, the team led by researcher Shoukhrat Mitalipov was able to remove a genetic mutation known to cause hypertrophic cardiomyopathy, a heart defect that affects 1 in 500 people and affects millions worldwide. If brought to term in a mother's womb, a resulting baby would be free of the life-threatening disease.

The OHSU team was not the first to attempt embryonic genetic modification—there were three previous studies in China. But Mitalipov says the success and scale of his study were unprecedented. "It was done on quite a few embryos," Mitalipov tells WW. "We were able to successfully repair [the genome] in 50 to 60 percent of cases. In previous studies, this type of repair happens in 1 percent of cases."

Shoukhrat Mitalipov (Natalie Behring)
Shoukhrat Mitalipov (Natalie Behring)

Why it mattered: For most of the 150 years since the discovery of genes, your biological heredity was considered an immutable fact of existence: DNA was destiny. An inherited genetic predisposition toward Parkinson's or Alzheimer's or heart disease meant your life was a time bomb with an uncertain fuse.

But Mitalipov's research promises the possibility of eradicating genetic disease one embryo at a time—a lead foot on the gas pedal of evolution.

Human embryos (ZEISS Microscopy/Flickr)
Human embryos (ZEISS Microscopy/Flickr)

The editing of a human embryo also challenges assumptions about what it means to be human. The U.S. intelligence community has listed CRISPR gene-splicing technology as a potential "weapon of mass destruction." Congress, fearing designer babies and unintended consequences, has banned the U.S. Food and Drug Administration from approving studies that would allow gene-edited embryos to be brought to term.

Mitalipov says we shouldn't halt progress on a cure because of hypothetical abuse, adding that his technology can only eliminate known mutations that cause diseases.

"If we believe changing genes for enhancement is bad, it can be regulated," he says. "[Gene editing] can eliminate the suffering of a child. This could benefit millions. It's still a concept, but we think this will be one of the huge medical developments of the future."