What to watch with VDR and fertility?

The vitamin D receptor (VDR) is involved in vitamin D metabolism, and vitamin D is important for fertility (egg maturation, sperm quality, implantation). Some studies suggest links between certain VDR polymorphisms (e.g., FokI, TaqI) and fertility parameters, but the evidence is mostly mechanistic and insufficient for clinical recommendations. Consumer DNA tests often list VDR as a 'fertility marker,' but effect sizes are small, and lifestyle, nutrition, and other genetic/environmental factors are more relevant. Vitamin D deficiency should be assessed by a doctor – a genetic test alone does not replace a blood test. Beware of overblown claims: most VDR variants have no clearly established impact on fertility.