Genetically Engineered Babies Are Banned. Tech Titans Are Trying to Make One Anyway.

For months, a small company in San Francisco has been pursuing a secretive project: the birth of a genetically engineered baby.

Backed by OpenAI chief executive Sam Altman and his husband, along with Coinbase co-founder and CEO Brian Armstrong, the startup—called Preventive—has been quietly preparing what would amount to a biological first. They are working toward creating a child born from an embryo edited to prevent a hereditary disease. In recent months, executives at the company privately said a couple with a genetic disease had been identified who was interested in participating, according to people familiar with the conversations.

Gene-editing technologies now in use for treatment after birth allow scientists to cut, edit and insert DNA, but using the process in sperm, eggs or embryos is far more controversial and has prompted calls by scientists for a global moratorium until the ethical and scientific questions get resolved. Editing genes in embryos with the intention of creating babies from them is banned in the U.S. and many countries.

Preventive has been searching for places to experiment where embryo editing is allowed, including...