He Jiankui's CRISPR Babies (2018)

Chinese scientist He Jiankui used CRISPR gene editing to modify the embryos of twin girls, Lulu and Nana, claiming to make them resistant to HIV. The announcement shocked the scientific world — not because gene editing doesn't work, but because he bypassed ethical review, used it on viable embryos, and introduced unknown off-target mutations into the human germline. He was sentenced to three years in prison. The twins' long-term health remains uncertain and the experiment opened a Pandora's box of heritable genetic modification.