Gene therapy

In this April 2019 photo provided by the St. Jude Children's Research Hospital, 2-year-old Gael Jesus Pino Alva is held by his mother, Giannina Alva, at the hospital in Memphis. Gael was one of eight babies with "bubble boy disease" who have had it corrected by gene therapy that ironically was made from one of the immune system's worst enemies, HIV, the virus that causes AIDS. (Peter Barta/St. Jude Children's Research Hospital via AP)