Evidence check: ACTN3 in the context of Fruchtbarkeit

The evidence for a link between ACTN3 (alpha-actinin-3) and fertility is very weak. ACTN3 is primarily known for its role in muscle fiber type determination and athletic performance (R577X polymorphism). A few small studies have explored possible associations with sperm quality, but results are inconsistent and not replicated. There are no robust human studies demonstrating a direct effect on male or female fertility. The proposed mechanisms are speculative. Therefore, the evidence level is best described as 'unclear' or 'mechanistic'. Consumers should not rely on ACTN3 test results in the context of fertility.