Similar to the results for self-reported genital herpes, the frequency of clinician-observed genital ulcers did not vary by genotype, with an aOR of 1.2 (95% CI: 0.9–1.6; p = 0.31) for African Americans and 0.8 (95% CI: 0.5–1.4; p = 0.50) for European Americans comparing IFNL4-ΔG/ΔG or IFNL4-ΔG/TT genotype to IFNL4-TT/TT genotype; results for African and European Americans combined were: aOR 1.1 (95% CI: 0.8–1.4; p = 0.53). Here, IFNL4 is linked to genital herpes.