There was no significant causal effect of serum iron (OR = 0.99, 95% CI: 0.72–1.37, p = 0.951), ferritin (OR = 0.88, 95% CI: 0.47–1.64, p = 0.676), and transferrin saturation (OR = 0.89, 95% CI: 0.72–1.09, p = 0.252) on autism. This evidence concerns the gene TF and autism.