Why does inbreeding cause birth defects?

Question

Why does inbreeding cause birth defects?

In: 3

Answer 1

The bad traits are amplified.

Think of someone receiving a 10% chance of getting a gene that causes cancer. Now if two parents each have a 10% chance of spreading cancer, the cancer is more likely to be passed on to the child. Now the child has a 20% chance of getting cancer and contains the gene to pass it on. They have offspring with a person who has a 20% chance and the likelyhood goes up to 40%.

Those numbers actually don’t completely work in real life, it is vastly simplified for the CMV. It just comes down to likelyhood.