What role does Transferrin play in fertility?

A direct-to-consumer (DTC) DNA test typically analyzes single SNPs (e.g., rs1800012 in COL1A1) and provides risk indications that often represent weak associations. A clinical genetic test is ordered by a physician, performed in an accredited lab, and can yield diagnostic or predictive results with high validity (e.g., BRCA1/2). DTC tests are not diagnostic but may serve as screening tools – positive results must always be clinically confirmed. The evidence for DTC SNPs is usually 'gwas' or 'mechanistic', rarely 'human-strong'. Additionally, context factors like environment, diet, or epigenetics are often missing. For serious medical decisions, a clinical test with genetic counseling is essential.