Britain is one step closer to legalizing “three-parent babies”—babies created from the DNA of three people. This week the House of Commons approved legislation allowing the controversial procedure, which is intended to prevent incurable genetic diseases from being transmitted to infants. However, some faith groups and ethicists warn that it could be used to create “designer babies.” If the bill passes the House of Lords, Britain would become the first country in the world to legalize the procedure.