What Kind of Birth Defects are possible when a sister marries her brother and has a child?

Question

Because its illegal i wondered if birth defect were why

Answer 1

club feet, vision problems, retardation, hunchbacks, cerebral palsy, the list goes on and on.

Answer 2

Birth defects are not created by incest.
Incest does not cause mutations.
Most people have recessive genes - if both parents have the same recessive gene, then the child might have the gene expressed, with no dominant gene to mask it. That is true whether or not the parents are related.
Not all recessive genes cause birth defects when expressed - Red hair can be a recessive trait, for example, but it is not a defect. The chance of a recessive trait being expressed in a child of an incestuous relationship is only a few percentage points higher than the general population. You get more birth defects from living too close to the wrong factory.
The REAL reason incest is illegal is because of an uncosncious reaction, or instinct, that people have to avoid sex with close family members, and anyone else who lived in their house when they were growing up. It's called the Westermarck Effect. If you live with a person from the time you were born up until about the age of six, this instinct to avoid sex with them is triggered.
Laws and excuses about birth defects are just rationalizations for this instinctive reaction. It makes sense from an evolutionary point of view - it's better to mate with as divergent a gene set as possible, to encourage greater viability in the offspring and less vulnerability among an isolated population to changing circumstances.
(in other words, exotic is attractive, and makes better babies. That's why there are so many interracial marriages these days.)
If there are going to be birth defects, they can probably be found by looking into the family history. Some families are prone to diabetes, weight gain, hemophilia, weak cardiovascular problems, and high cholesterol, to name a few.
What people fail to mention, however, is that the child of incest is just as likely to show genetic ADVANTAGES. Some families are prone to strong bones, plague resistance, survival under starvation conditions, high pain threshholds, excellent eyesight, high stamina and good teeth, to name a few.

Answer 3

Honestly (wrongness aside) not much more chance than the baby of unrelated parents, and the same basic problems. Royal Famlies did it pretty commonly in some bloodlines it takes a few generations for there to be a major ongoing, and worsening problem. People still do it occassionaly in animal breeding, you just have to know how closely they were related in earlier generations to avoid trouble.

It's illegal for many reasons not just because a one time pairing would create exeptionally defected children.

Answer 4

Birth defects are highly possible. Lots of defects: retardation, mental issues, fingers and toes missing or conjoined, club feet, cleft lip, and on and on and on. How could any one marry their brother? Like you said it's illegal and there is no way a marriage license would be granted.

Answer 5

Did you ever see the movies "wrong turn" and "the hills have eyes"? Those kind of children

Answer 6

I dont know but that is gross, and i really do feel for the poor little baby that is stuck in the middle of all of this!!

Answer 7

oh gosh, anything and everything could go wrong. you name it, baby will have it. And yes that is part of the reason it is illegal.

Answer 8

I hope you just want to know this info and not that you are considering this personally.

Answer 9

just think DELIVERANCE.