The article discusses the challenges and best practices for replicating genotype-phenotype associations, particularly in the context of genome-wide association studies (GWAS). It highlights the importance of replication in establishing the credibility of genetic associations and addresses the issues that often lead to failed replications, such as small sample sizes, poor study design, and lack of comparability between cases and controls. The article also emphasizes the need for rigorous statistical methods, including permutation testing and robust methods to handle multiple comparisons. It provides guidelines for the design, conduct, and publication of replication studies, including detailed checklists for reporting study information, genotyping procedures, results, and replication attempts. The article concludes by emphasizing the importance of open data sharing and the need for journals to publish both positive and negative findings to ensure the integrity and progress of genetic research.The article discusses the challenges and best practices for replicating genotype-phenotype associations, particularly in the context of genome-wide association studies (GWAS). It highlights the importance of replication in establishing the credibility of genetic associations and addresses the issues that often lead to failed replications, such as small sample sizes, poor study design, and lack of comparability between cases and controls. The article also emphasizes the need for rigorous statistical methods, including permutation testing and robust methods to handle multiple comparisons. It provides guidelines for the design, conduct, and publication of replication studies, including detailed checklists for reporting study information, genotyping procedures, results, and replication attempts. The article concludes by emphasizing the importance of open data sharing and the need for journals to publish both positive and negative findings to ensure the integrity and progress of genetic research.