I think laws forbidding cousin marriage are unfair and should be the next target of civil rights activism. Incest laws in general makes no sense except as a eugenics measure. Either we dump these laws or we judge all eugenic measures that rise above it in the cost-benefit metric as acceptable. Else we are just picking and tormenting loving couples because of some historic baggage.

And where is the transhumanist spirit? Technology lets a brother and a sister have as healthy a baby as anyone else's.

Edit: Added the eugenic argument, I originally didn't think I would need to.