In November, Dr. He Jiankui announced that twin girls had been born in China from embryos whose genes he had altered using CRISPR gene-editing technology. According to the magazine Science, he hoped to build a baby-designing business. In March, a World Health Organization committee argued for a moratorium on clinical human genome editing "until its implications have been properly considered." But no system of global guidance exists to implement or enforce such a ban on the practice. In June, a Russian scientist declared that he plans to proceed anyway. You can imagine what bad actors with eugenic fantasies could do with this technology. But today, many parents, with the best interest of their future children in mind, choose embryos based on the genes inside. Since 1978, when the first child, Louise Brown, was born using in-vitro fertilization, this and other assisted reproductive technologies have expanded immensely, creating over a million babies. Because preimplantation genetic diagnosis allows parents to avoid transmitting mutations to children, CRISPR will unfortunately probably be used to enhance progeny with socially desired traits such as height, certain athletic abilities or intelligence. Such uses will be very profitable. Due to high costs, assisted reproductive technologies, including preimplantation genetic diagnosis, are not available to everyone and are thus altering how thousands of affluent people -- but not poorer individuals -- thrive and live.