Is dating a cousin bad
Culture aside, the underlying issue is whether cousin marriages are genetically safe for the resulting children. One recent study suggests that children of cousins face a 6% risk of birth defects, vs. But please don't stop reading here, because it's a little more complicated than that and this number is probably much too high."Advocates (of cousin marriage) point out that this resulted in for the children in the study, as compared with a 3% chance for the population as a whole.
For your reference, this increase in birth defect rate is about the same as the increased risk of a woman having a baby when she is 40 vs. Proponents here point out that few would advocate banning a 40 year old women from having children.
They also point to recent testing that placed the increased risk of spina bifida and cystic fibrosis at only 1.7% -2.8% higher than for children of unrelated parents.