Researchers in New York are investigating whether it is possible to edit the genomes of human sperm, NPR reports.
A team at Weill Cornell Medicine led by Gianpiero Palermo is attempting to edit sperm using the CRISPR gene-editing tool with the ultimate goal of preventing genetic diseases passed down by fathers, including male infertility. NPR adds that the team is first tackling editing the BRCA2 gene, which is linked to an increased risk of breast, ovarian, prostate, and other cancers.
The effort, NPR notes, is marked not only by technical issues — DNA in sperm is compact, making getting the gene editing machinery in there difficult — but also the same ethical issues as other efforts to alter the human germline. He Jiankui's announcement last November that he had edited the genomes of twin girls as embryos was widely condemned by researchers. Editing of sperm could be safer than editing of embryos, as a mosaic of edits is less likely when sperm rather than embryos are manipulated.
But, Françoise Baylis, a bioethicist at Dalhousie University, tells NPR "[i]t doesn't matter whether you're manipulating the embryo or you're manipulating the sperm."
"The concern is what kind of world are you creating as you move down the path to start manipulating human genetics," Baylis adds.