Monday, April 16, 2018

Just how bad is it to have kids with your cousin?

Image result for darwin and his wife

Acoording to a research done by Yaniv Erlich a scientist at ColumbiaUniversity and the Chief science of officer of the DNA test company MyHeritage  have looked into determining at what point in history marrying your cousin was frown upon and the chance of a baby being born with birth defects due to consanguinity. In today society marriage between cousin is oddly viewed but in earlier times, cousins used to get hitched all the time. Such as Franklin Delano Roosevelts who married his fifth cousin Elenor or Albert Einstein and Charels Darwin who married their cousins too. From the 1650 to 1850 and individual on average was on average, fourth cousins with their spouse. By 1950 married couples were on average seventh cousins, according to Erlich. There was more of an expansion between cousins marrying each other in a within a centuary beacuse before1950 most people married someone who lived within a six mile radius of where they were born. Of course other factors played a role in marriages between cousins which influenced families to marry between each other such as money, power and control of territory.
Now modern time many states moved to outlaw cousin marriage. Today 24 states ban marriage between first cousins, while 20 states allow it. The others allow first cousins to couple up, but only under certain circumstances which include only both are over 50 or 55 or 65. Depending on the state the marriage is allowed if one or both are permanently infertile and only if the couple has received genetic counseling. First cousin share 12.5 percent of their DNA while parents and kids share about 50 percernt. Therefore any child that results from first cosuin union will have a similar looking genes which can result in future problems. Its estimated that 4 to 7 percent of children born to first cousins are likely to have birth defects, compared o 3 to 4 percent for children whose parents are more distanltly related. The real issue would rise if the next generation of kids also married their first cousins because their offspring would have even more DNA in in common and an even greater chance for birth defects. Odds of healthy offspring improve with each distance of relation. Second cosuins share 6.25 percent og their genes and third cousins share just over 3 percent. Any further cousins for the most part have no meaningful genetic relation at all.


  1. This is very interesting !! It's amazing how many people take the chance with all these facts and side effects!

  2. This is an interesting topic to research. I didn't realize that only 23 states have laws against this, I personally believe it should be more. It is important that people realize they can bring a baby into the world with life threatening health risks and that is not fair to do.

  3. It is little disturbing that there are not more states that harbor a law against having a child with your cousin. If someone knowingly has a child with their cousin, then they are bringing a child into this world with already guaranteeing that it may have a defect and a struggle in life. The fact that 20 states allow you to marry your cousin is very surprising, I think it should not be allowed and more people should be educated about the side affects their child can have when keeping the bloodline within the family.

  4. I was unaware that only 23 states consider marriage between cousins to be illegal. Considering societies views and stigmas around incest, I assumed all states would have laws in place. I also found it interesting that up until the 1950's most individuals were still related to their spouse, however the explanation regarding expansions and the lack of travel individuals back then had, this makes sense.