Inbreeding is technically defined as the mating of animals more closely related than the average relationship within the breed or population concerned. For practical purposes, if two mated individuals have no common ancestor within the last five or six generations, their progeny would be considered outbreds.

What is the science behind inbreeding?

Inbreeding results in homozygosity, which can increase the chances of offspring being affected by deleterious or recessive traits. This usually leads to at least temporarily decreased biological fitness of a population (called inbreeding depression), which is its ability to survive and reproduce.

What is inbreeding and why is it a problem?

Inbreeding occurs when two closely related organisms mate with each other and produce offspring. The two main negative consequences of inbreeding are an increased risk of undesirable genes and a reduction in genetic diversity. The House of Habsburg may be the best example of the effects of inbreeding in humans.