What are the/some causes of conjoined twins?
102124
Conjoined twins occur when one egg splits to become two identical eggs. The day the ova splits determined what the identical twins will share. if the ova splits between 4-8 days after fertilization, the embryos share a chorion but have their own amnion.If the ova splits around the 8th day, embryos will share both a chorion and amnion. this type of twinning is called Monoamnionic/monochorionic. If the ova splits around the 12th day, the embryos will be conjoined.\n\n\nTypes of conjoined twins\n\n\nCraniopagus: Cranial union only, about 2% of all conjoined twins. \n\nPygopagus: Posterior union of the rump, about 19% of all conjoined twins. \n\nThoracopagus: Anterior union of the upper half of the trunk. The most common form of conjoined twins (about 35%), it always involves sharing the heart. \n\nCephalopagus: Anterior union of the upper half of the body with two faces on opposite sides of a conjoined head. Extremely rare. The heart is sometimes involved. A combination of types 3 and 4 is called epholothoracopagus. \n\nParapagus (sometimes called diprosopus): lateral union of the lower half, extending variable distances upward, about 5% of all conjoined twins. Heart sometimes involved. \n\nIschopagus: Anterior union of the lower half of the body, about 6% of all conjoined twins. Heart not involved. \n\nOmphalopagus: Anterior union of the midtrunk, about 30% of conjoined twins. \n\nParasitic twins: Asymmetrical conjoined twins, one twin being small, less formed, and dependent upon the other. \n\nFetus in fetu: Situation in which an imperfect fetus is contained completely within the body of its sibling.
302858
No, a clone would be exactly like an identical twin (though with a clone the two may be different ages).  Though there are a lot of reports of twins feeling when the other is hurt or dies, most twins interviewed claim this has never happened to them.  Regardless, even in those that claim to be able to "feel" the other's pain, there is no damage or lasting effect.  There of course may be psychological damage if, for example, you were raising your clone as a child or were close to them (as identical twins often are)-depression, grief, etc, but that is quite normal.
1180435
They were on Oprah a few years ago.  Look on the I'net for conjoined twins, vs Siamese.
278951
I think that everyone has to make their own decision. \nI don't feel that conjoined twins should be seperated. sure it might make their lives easier if the seperation isn't fatal, but maybe they were born conjoined for a reason. Maybe it is part of the greater journey that they are on.
796648
My two sons, my wife, and my mother-in-law all have chiari 1. My youngest son ( he's two 1/2  now ) was decompressed last year on Halloween. We've joined with Duke University to participate in genetic study to help determine the genetic and environmental causes of chiari.
1175424
Spina Bifida is caused when there is an incomplete development of the covering of the spine. Amniotic fluid does damage to the spinal column and that results in the disability. There are different forms of spina bifida and you can find more info on them at\n http://www.ninds.nih.gov/disorders/spina_bifida/detail_spina_bifida.htm#55953258\n\nHoped this helped some......
702400
Multiple births come from two sources.  First, sometimes more than one egg is released in a single cycle.  If multiple eggs are fertilized, fraternal twins (or triplets or whatever) result.  That's why you get so many multiple births with fertility drugs--they often force many eggs to be released at once to improve the odds, or implant multiple fertilized eggs in the hope that at least one will live.\n\nIdentical twins and triplets are grown from a single egg and a very energetic sperm, which strikes the egg so hard that it tears apart into two or three fragments, each of which becomes a baby.  These babies all came from the same egg/sperm combo so they have the same genetic information.  That's also why you don't see identical siblings more than triplets.  There's only so many pieces you can tear an egg into with one impact.\n\nIncidentally, conjoined twins also come from a sperm tearing the egg apart.  If it doesn't quite separate, the pieces of the egg will form into two babies who are attached where the egg didn't tear.
443822
A LOT OF THINGS! There could be cancers, exposure to radiation, brain damage, birth defects. There are alot of chemical factors that are hard to understand but there is no ACTUAL cause. INdustrial chemicals like Vynil chloride could cause it, but thats justlike the radiation exposure. Mutations, depletions of your "brain immune system" hahahhaa can deplete your tumor supressor genes.
424693
i also have twin sons and get asked if they are twins all the time. No idea why...Another thing that drives me nuts is when they say, "You really have your hands full, don't you..." No S**T Sherlock!
515757
identical twins result when the fertilised egg splits into two, and one of them splits again to form triplets.\n\nNon-identical twins/triplets result from more than one eggs being fertilised
1044618
My sister and I are identical twins.\n\nOnce, someone asked us if we ever got ourselves mixed up! (Really!)  :-))
344530
This is called Chimera. After the mythological beast which had body parts of different sets of animals.\nA Chimera will usually have their blood and tissue of one DNA, while their reproductive organs and some inner organs will be of another. This is fairly random as to the "where" and "what," and it usually comes up as a concern in DNA testing when a mother is seemingly not the parent of her child. Or in crime cases where they cannot identify the rapist based on semen.\nThis condition occurs when two twins are begining to form within the womb, and for whatever reason one twin dies--and the other cell takes on the DNA--as a "clean up" if you will. The result is that the one cell finds no reason not to use the perfectly good DNA, and incorporates both wherever it sees fit.
775861
After conception, the single fertilized egg begins to multiple and divide. Up to a point all of the cells are identical. That is why it is possible to have identical twins.  If at some point the dividing cells increase their number so suddenly that a section of cells actually get  bumped away from the main body of cells the second set of cells are identical to the first. If that second set can attach to the wall in time it will develop into an identical twin.\n\nAt this point the identical cells are called STEM cells. They have no individual identity and they are completely interchangeable.  \n\nIt is a mystery that still puzzles researchers as to how the "triggers"  turn on to tell one area of cells to become brain, another liver, another lungs, etc.  But they do.  The really amazing thing about that is that the body produces those cells even after we are born. I believe it occurs in the bone marrow.\n\nResearchers are trying to find ways to coax those stem cells out of our body and place them into damaged areas to create new cells. Stem cells inserted into a dieing pancreas will become pancreas cells because they take on the identity of whatever cells they come into contact with.\n\nThey could be inserted into a diseased heart or lungs, or liver to grow new healthy cells.\n\nThey all carry the same genes because they come from the same donor. \n\nIt truly is a mystery....
283993
Strangers.  Twins or triplets, or whatever cannot be born at the SAME TIME.  However, you never stated they had the same mother, so two different women gave birth at the same time.  Nothing too strange about that, even if they are strangers!
952837
Twins are so connected that they don't realise they are one and the same.  They both share some attributes but are also like  chalk and cheese on others.  Understanding this is the beginning of understanding what makes us different but also what bonds us.
329942
There's no connection b/w being a twin and having a cleft palate. A cleft palate occurs when the right and left sides of your palate fail to join/fuse. Identical twins are born when a fertilized egg and sperm splits into two.
1138453
They will separate the body from the living twin and attempt to construct the features as close to normal as possible.  The other twin would die, on the other hand, if some major artery or organ was shared that shuts down after the other twin's death.