On the eve of publishing her new book , Jennifer Doudna, a pioneer in the field of CRISPR-Cas9 biology and genome engineering, spoke with Fast Company about the potential for this new technology to be used for good or evil.

“The worst thing that could happen would be for [CRISPR] technology to be speeding ahead in laboratories,” Doudna tells Fast Company. “Meanwhile, people are unaware of the impact that’s coming down the road.” That’s why Doudna and her colleagues have been raising awareness of the following issues.

Related: CRISPR Pioneer Jennifer Doudna On Gene Editing’s Potential For Good And Evil

Designer Humans

Editing sperm cells or eggs—known as germline manipulation—would introduce inheritable genetic changes at inception. This could be used to eliminate genetic diseases, but it could also be a way to ensure that your offspring have blue eyes, say, and a high IQ. As a result, several scientific organizations and the National Institutes of Health have called for a moratorium on such experimentation. But, writes Doudna, “it’s almost certain that germline editing will eventually be safe enough to use in the clinic.”

Gene Bombs

Using a CRISPR-related technique known as gene drive, bioengineers can encode DNA with a selected-for trait, which propagates to future generations—and across entire populations—with unnatural speed. This could give mosquitoes resistance to a parasite responsible for malaria or encode them with a gene for female sterility—thus breeding the pests themselves out of existence. But there’s also the risk of spreading unwanted mutations and crossbreeding the change into another species. “There could be real dangers to releasing organisms into the environment that are out of control at some level genetically,” Doudna writes, “where there’s some trait that’s being driven through a population before we understand what the implications of that really are.”

De-Extinction

Woolly mammoths roaming the earth once again? It’s far from easy to do, but scientists are working on just such a Jurassic Park scenario. “Ever since I first heard about experiments like these, I’ve struggled to decide whether they’re admirable, deplorable, or something in between,” writes Doudna. They could enhance our planet’s biodiversity, but bringing back certain species could also open the door to dangerous pathogens or upset ecosystems.

Altering Nature

Since CRISPR’s discovery, scientists around the world have been finding new ways to apply gene editing to plants and animals. Here are some of the developments Doudna tracks in A Crack in Creation.