Yeah, that's the family history of inbreeding that I was talking about - if you continuously have children within the family for multiple generations then the risk continues to rise so long as the trend continues. It's generally only the risk of getting 2 copies of some familial recessive condition or other issues that arise from getting identical copies of genetic information from both parents, though, so breaking the chain and having a kid with someone outside of the family removes that risk; even if someone has a family history of inbreeding, it doesn't put their potential children at risk so long as their partner isn't related to them.