Question: How is reproducing with a family member bad for the baby???

Laurent Dupays answered on 19 Jun 2018:

This is a really good question and I will try to answer. Each person carries two copies of the same gene: the two alleles of a gene. Most of us are carrying mutations in one of our allele and make it faulty. Fortunately, the good allele is taking over and we are fine.
Parents that are closely related have a higher chance of sharing the same faulty alleles, and if you inherit two faulty alleles, one from each parent, there is a risk of passing on possibly harmful traits to your baby.
So yes reproducing with a family member is really bad for the baby!