The researcher who pioneered prenatal surgery to correct neural tube defects has turned her attention to using CRISPR-edited gene therapies to correct severe monogenic diseases in utero. The availability of prenatal genetic diagnosis and advances in treating fetuses, and also in gene therapy/gene editing, make it possible to repair almost any defect in the genetic code. At the same time, there is a clear rationale for intervening before birth, Tippi MacKenzie, professor of surgery at UCSF’s School of Medicine, told attendees of the third International Human Genome Editing Conference in London on March 7.