He intentionally dodged ethical review and the law, the consent forms he had the parents’ sign obfuscated the nature of the treatment, the experimental treatment offered no benefit over the currently used treatment to prevent HIV transmission from the father (sperm washing), the parents likely only agreed because the law prevented them from having biological children (IVF isn’t available to HIV+ patients in China), the high risk of modifying non-target genes was well known, and the gene he introduced is believed to be linked to neurological differences.