UN Resolution Fifty-one, also known as the "Khan's Stepchildren" resolution, was a law that was made by Earths United Nations in the 21st century in the aftermath of World War III as well as the Eugenics Wars. This resolution was one out of two thousand and thirty eight which determined that no citizen of Earth could be held liable for the acts of their ancestors. A rider to this resolution later confirmed the Human status of certain Human variant strains who had been created in the gene research laboraotires which created Khan Noonien Singh and the Augments.

In 2270, Spock mentioned this resolution to the genetically engineered Human offshoot colony on the planet Okeanos. (TOS novel: From the Depths)