CLOCK and Infertility: A statistically significant difference in haplotype distributions was also confirmed at the CLOCK gene locus when comparing the frequencies of haplotypes TCAG (p = 8·10−5, simulated p value after 10.000 permutations was 5·10−5), CCGG (p = 8·10−3, simulated p value was 8·10−3) and CGGG (p = 0.04, simulated p value equaled to 0.04) between the infertile patients and fertile controls.