The invention encompasses the discovery of sex-specific genetic loci, including primers (oligonucleotides) for their amplification, which enable to determine the sex of an individual from a DNA sample by quantitative polymerase chain reaction in anguimorphan lizards, especially monitor lizards, beaded lizards and some anguids. The invention also provides instructions for finding additional pairs of oligonucleotides suitable for sex determination in this group of lizards.