The data on first-cousin marriage is damning — children of first cousins are nearly three times more likely to die by age 10 and 90% more likely to have learning difficulties, yet NHS guidance tried to spin this as a cultural trade-off worth tolerating. Societies built on prohibitions against kin marriage developed the individualism and openness that define Western success. Allowing this practice to go unchallenged blocks assimilation and puts identity politics above children's health.