The Longterm Effects of Incest and Inbreeding

The Longterm Effects of Incest and Inbreeding

In some places in, the United States, folks make jokes, about inbreeding,. My own mother was, from West Virginia, and some of her friends, would often make “pumpkin head” jokes about the inbred folks where she came from. (It is true that her parents, my grandparents, were second cousins; however, both my mother and her brother were adopted.)

For a long time, the dangers of inbreeding or having children with a close relative weren't completely understood. The biggest problem with inbreeding is that when close relatives choose to mate, it results in homozygosity, which can increase their offspring's chances of being affected by deleterious recessive traits for all kinds ofphysical and cognitive disabilities, including ailments like hemophilia and cystic fibrosis as well as deformities like the Habsburg jaw. These incestual pairings also run a greater risk of...

• Reduced fertility (both for the related parents and in their offspring)
• Lower birth rate and higher infant mortality
• Congenital birth defects (including facial asymmetry)
• Certain kinds of cancer
• Suppressed immune systems
• Smaller adult size (pedigree collapse)

These days, we have genetic testing and other valuable research tools to help us determine what may happen if we have kids with someone who is biologically related to us. But up until just a few centuries ago, it was common practice for people to marry their cousins and even their brothers and sisters (and in many remote rural regions, the practice continues today).

Historically, family line relations were often formed in royal houses to secure political alliances, strengthen the lines of succession, and ensure the noble purity of the bloodline. This practice caused a host of ailments and deformities that can still plague descendants of these royal houses to this day.