A method of preventing transmission of a retrovirus from a mother to her offspring, by treating the mothers host cells with a composition comprising a Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-associated endonuclease, and two or more different guide RNAs (gRNAs), wherein each of the at least two gRNAs is complementary to a different target nucleic acid sequence in a long terminal repeat (LTR) of the proviral DNA, and preventing transmission of the proviral DNA to the offspring.
