First, the potential for good. With regard to hereditary human disease, such as thalassemia, cystic fibrosis, or even color-blindness, this technique can be used to find and replace defective genetic mutations in the eggs at the same time as fertilization with sperm occurs. Following correction, the new DNA sequence would then be passed to any offspring of a genetically modified child. In this “germline engineering” process, the DNA replacement would only have to happen in one generation for the changes to be inherited by his/her children, grandchildren, great-grandchildren, etc. Could this be the end of hereditary blood disease or even hereditary cancer, preventing disease before the baby even begins to develop?
Unfortunately, we’re not quite there yet. Although this has been the first successful human experiment in the U.S., China has been performing similar research for several years, and they’ve noticed a few drawbacks. The editing process still made a number of errors while trying to change the genetic code. Not only did CRISPR sometimes modify cells that weren’t meant to be changed, but it didn’t always change all of the cells in the embryo that it was supposed to.
Also, the morality of changing DNA in humans is still up for debate. While the U.S. Academy of Science approved the process for elimination of dangerous diseases, CRISPR is not approved for enhancement of abilities, at least in the U.S. So, if you were hoping to build the world’s most beautiful baby who not only had an IQ of 200 but also could dunk a basketball like Lebron James or throw a football like Tom Brady, you’re going to have to wait awhile. In fact, that’s one of the big moral concerns for many religious groups: is use of this technology to design the perfect baby like trying to usurp God?
For now, the debate continues about the amazing treatment potential and also the scary potential for abuse of germline engineering, so babies will have to continue to be made the old-fashioned way. That being said, isn’t your child the perfect little angel anyway 😊