CRISPR technology has revolutionized the field of gene-editing with its ability to cut and paste bits of DNA but also carries big ethical questions and unknown risks.

Previously thought of as the work of science fiction it is now touted in headlines as one of the biggest scientific breakthroughs.

While still in the early stages of research, CRISPR’s future potential to cure genetic diseases and alter mankind has been the subject to many ethical and scientific debates.

“[CRISPR] could revolutionize a lot of things in medicine and there’s a lot of promise, particularly with cancer,” University of Toronto bioethicist Kerry Bowman told CTV’s Your Morning on Friday.

He explained the potential to use it to alter a person’s immune cells so that they would target cancer cells in the body and reprogram them.

“But it’s going to take some time to get it from the lab to the bedside,” he said.

CRISPR has also shown promise in mice for eradicating diseases such as HIV, as it’s able to literally remove the disease from the gene sequence.

“But with this comes risk,” Bowman warned. “In a lot of the early trials, particularly the early trials done on human embryos, […] there was a lot of what’s called off-target.”

Off-target is when the intended gene-editing effect has unexpected consequences. For example, imagine your genes are a giant tangled mess of Christmas lights. Sometimes if you take out one faulty bulb it fixes the problem but other times the entire string goes out or half the string starts flashing.

The same thing can happen if CRISPR removes the gene for a disease. It might solve the problem but it could have a knock-on effect with another gene that controls a vital function.

“Genes are very complicated and as we learn more about genes we realize that genes affect other genes. So it’s not completely clear what the potential side effects from some of the CRIPSR interventions could be,” Bowman explained.

And it’s not just diseases that CRISPR can alter; it also has the potential to change human evolution.

While it’s still not possible to override natural selection, earlier this year, scientists in the U.K. and the U.S. were granted permission to alter human embryos, which could affect generations to come.

“That’s affecting what is called the germ line,” Bowman said, “What that means is if the child is born and you’ve altered the child’s genes, if that child goes on to have children, those genetic changes will go on through the generations. It could take decades or maybe generations to find out what some of the negative effects would be.”

According to Bowman, changing “the human story” also brings up big ethical questions and implications for our society.

“What we’re doing is creating a new kind of person and a new class of person. Society already has enough prejudices,” he said.

“CRISPR has great potential but we can’t lose sight of the ethics and we’ll have to move very cautiously with it and think it through.”