Regeneration is being worked on. Some such genes are already present in the human genome but they need to be switched on, and off, appropriately.
Natural regeneration in humans
In humans, the only tissue that regenerates naturally, consistently, and completely is the endometrium.1 After it slough-offs during a woman’s menstrual period, it grows back by re-epithelialization until the next period. Humans can also regenerate an injured liver provided that the restoration involves as little as 25% of the original liver mass. The liver can grow back to its original size but may not to its original shape. Damaged tubular parts of the kidney can also re-grow. The surviving epithelial cells undergo migration, dedifferentiation, proliferation, and re-differentiation to set a new epithelial lining of the tubule.
https://www.biologyonline.com/articles/regeneration-in-humans-finding-the-gene-switch
