A new piece in The New York Times Magazine looks at the growing controversy surrounding three-parent fertilization. The procedure introduces a donors cytoplasm into the mothers egg, potentially adding a third parents genetic data to the child, but effectively treating mitochondrial disorders and a range of infertility issues. As the science develops, its also become the center of a heated battle around genetic ethics. Three-parent IVF is the first technique to alters the germ line, disrupting the natural flow of genetic information from parent to child.