Why do people say if you marry a relative....?

It is actually culturally acceptable to marry a first cousin in many places in the world. It is even legal in sone states in USA.

As long as it is not generation and generation marrying relatives, there really isnt a risk of any birth defects.

It's a matter of genetics.

Not that this is really an equal comparison, but look at dog breeding. A lot of disreputable breeders will just keep breeding the same dogs over and over again, or breed a dog and a close biological relative. The results can often be instability of character, physical defects and unpredictible behavior (i.e., a dog snapping).

One human example is the European Royalty of the 1700s-1800s. Members of the Royal Families for countries were only allowed to marry other royals, which limits the gene pool significantly. Over a few generations, conditions like haemophilia (genetic disorder that prevents blood from clotting) would show up.

The occasional close-relation marriage is not likely to cause a noticeable problem, but repeated in-breeding will expose the weaknesses in a DNA strain.

An honest question is not a stupid question.

Answer: Because of the similarities in your DNA, two close relatives have a much higher chance of producing children with birth defects or genetic illness than two people who are not closely related. Let me explain.

Our DNA is made up of many 'genes'. A gene is a piece of DNA which, for now, we will say tells your body how to build itself, what kind of traits that body will have (like body shape, skin color, blood type, etc;). Genes come in pairs- most people have two of each gene: one which we got from our mother, and one which we got from our father.

Most of the time, one of the genes in a pair is dominant, and the other recessive- that means that one gets used and the other doesn't. (There are exceptions to this, but it isn't important to your question.) Example: Let's say that the gene for brown eyes is dominant, and the gene for blue eyes is recessive. If you have one gene for brown eyes and the other is for blue eyes, then you will have brown eyes. To have blue eyes, you would have to have two genes for blue eyes, because it is recessive.

Now, we all have some defective genes, genes that don't work quite right. Most of the time these genes are recessive, so a dominant gene that does work right covers it up. This works because all our DNA is different, so if 2 people have a child, there is a good chance that if one has a bad gene in a particular area (like a gene that causes cancer, or mental retardation), the other will have a good gene to cover it.

But if you have a child with a close relative, it works a little different, because your DNA isn't as different. You have alot more genes in common because you are related, and have inherited genes from some of the same people. That means that chances are, if you have a bad gene, so does the other person. So the two bad genes together make a bad result- a genetic disease or birth defect.

Sometimes even people who are not related will have two bad genes in the same pair, but close relatives have a MUCH higher chance of this happening.

I've tried to keep this as simple as possible. There are alot more complexities to this, and if you are interested, you might try doing some research on DNA and genetics. There is certainly alot more to learn! Still, I hope this helps, and God bless!

Your question is not stupid.

People don't know jack squat about genetics. They believe what they overhear from "reputable" sources and don't bother to do the research foot work themselves.

Yes, being related (cousin/cousin) to your mate does increase your chances of a genetic issue arising in your offspring HOWEVER, it doesn't raise it all that much. (Just one or two percentage points) If your family marries cousin after cousin after cousin then and ONLY then are the chances very high for genetic issues. (think of Royalty and their issues with hemophilia)

If your talking about sister/brother, or mom/son, or dad/daughter relations then your chances for genetic issues are higher than that of cousin/cousin because you have more related genes. (at and/or more than 50% of the same genes)

As far a law is concerned. In the USA, over half of the states allow for the marriage of 1st cousins and all states allow for the marriage of 2nd cousins. In the majority of the rest of the modern world have NO restrictions on cousin marriage. No country (that I have found) allows for the marriage of sister/brother or mom/son or dad/daughter

In the end, don't take my word for it. Look it up on line, in books and do the research yourself.

It is in your genetic makeup and the fact that "inbreeding" will cause birth defects is a known fact. look it up online under genetic defects from inbreeding. it happens to animals too if they breed with their brothers/cousins...some have no eyelids some are born slow some are born with heart problems. it is really very sad.

its not a proven fact

its actually a mutated gene that makes a child have down syndrome or a with a disorder

not because you have children with a relative

but it is kinda weird dating a relative

My boyfriend's parents are cousins. In other countries and areas of the world, this practice is considered "normal". His brother has a few health problems, my boyfriend has weak eyesight, but his sister is perfectly fine. I don't think its "retarded" if you marry your cousin. Maybe if it was a sister or brother...or dad or mom or something. That would be WEIRD.

:)

oh by the way...they are first cousins...

because it's true. you and your relatives have some of the same chromosomes and it is a proven fact that when people with some of the same chromosomes make a baby together, the baby has a much much higher chance of having health problems.

That's if you marry a first or second cousing (I believe). I do know that it is unlawful in some states to marry a cousin.

the earth is populated enough so u dn't have to marry cousin's.