I saw someone had asked if identical twins can be opposite sex. Discovery channal said yes they can be.?

Question

I saw someone had asked that question and was told no identical means just that it is identical. Yet when watching the discovery channel it stated that identical twins could be opposite sex because at conception there was an extra "X" chromosone and then they split apart and caused a set of identical opposite sex twins.
Yet at the same time this show also stated that it is beleived most left handed people are results of their mirror image twin vanishing during the preganancy.
Has anyone else ever heard that before?
I always considered prior to watching that show that identicals were same sex.

Answer 1

identical twins cannot be opposite sex they need to be same sex, identical twins are from the same egg splitting after fertilization from 1 sperm and they both are either boys or both girls... opposite sex twins means 2 eggs were released from the Fallopian tube and both got fertilized and one was boy one was girl, they can also be boy and boy or girl and girl and not be identical just born on the same day

Answer 2

1

Answer 3

It is within the realm of possible but highly improbable that two children from the same fertilized egg would come to be opposite sexes. I can think of one way it could happen, however, although I'm not sure it was the way mentioned on the Discovery Channel. I'm not a scientist, however, so I cannot verify that what I have heard is true.

Normally, anyone with an XX chromosome is a female, the "default sex" in human beings, while people with an XY makeup usually switch gears and develop into males. Here is why: the X chromosome has the gene that first prompts testosterone production. (Both sexes have this hormone). If the fetus has no Y chromosome, it continues developing into a female. If the fetus has a Y chromosome, the presence of the hormone triggers a gene on the Y that directs the embryo to step up testosterone production to much higher levels. Once these male levels of testosterone reach a certain threshold, they trigger a second gene on the X chromosome, which tells the embryo to turn into a boy.

An XY person can continue developing as a normal female if the gene on the Y is defective and does not respond to the presence of testosterone. Basically, sex development goes on as if the Y were not even present. An XY person can also stay female if the Y works and orders the stepped up production of testosterone but the second gene on the X is defective and does not respond to the elevated testosterone levels. Because the hormonal makeup is more male than in normal females, however, this girl probably will not develop normally. She will probably be infertile and have other complications.

It is also possible for an XX person to become a male. This could happen where the second X gene that tells the body to make a boy goes haywire. It either fires off by itself or is abnormally sensitive to the presence of normal testosterone levels. He will have less testosterone than a normal male, however, so would probably be infertile and lack certain masculine traits. It is also possible for an XX embryo to become a normal male, but that is more rare. In addition to the defect on the second X gene, there also has to be an abnormality earlier in the process that causes elevated testosterone production. I'm not sure if the first X gene directs an abnormally high amount of testosterone production or whether somehow the instructions from the first X gene get garbled and end up in increased production that way.

In short, if the egg splits apart, you can get children of opposite sexes if one fetus develops in the ordinary fashion while the other has one of the above defects that causes it to develop as the opposite sex.

Answer 4

How Multiples Are Formed

"How twins are formed:

Identical twins are caused by one egg being fertilized by one sperm. Sometime after fertilization, the egg splits into two genetically identical halves. Identical twins are always of the same sex (although there has been very rare, as in only about 4 cases, of opposite sex identical because of genetic abnormality). They share 100% of their genes, and are in reality, natural clones.

Fraternal twins are formed when two eggs are released by the mother, and each egg is fertilized by a different sperm. Fraternal twins can be of the same or opposite sex. They share up to 50% of their genes, and are no more alike or different than any two siblings would be. It is also possible for fraternals to be of different races or parentage, or to be conceived at different times, resulting in a large weight difference at birth.

There is a third type of twinning that scientists are looking into, called polar body twinning, or "half identical" twinning. This occurs when the mother's egg splits before fertilization and then each half is then fertilized by a sperm. This may explain why some fraternal twins (such as the Olsen twins) look as alike as some identicals, but it hasn't been proven that it occurs.

Conjoined twins form exactly like identical twins, but at some point during the stage where the single egg splits, the process stops, and the twins develop attached to one another. This occurs in about 1 out of every 100,000 live births, but 60% of conjoined twins are either stillborn or lost in utero. "

Answer 5

i highly doubt that. identical means the twins are from the same exact egg and that egg has split to make two zygotes!! it's literally a copy, so no sex chromosomes are gunna change. if one twin is a female and one is a male, that means there fraternal. twins can look exactly alike, but still be fraternal. you know mary-kate and ashley are fraternal? its just rare; a 1 in 5,000 chance that fraternal twins will look so similar. but theres no chance identical twins can be different sexes..

Answer 6

I am familiar with this, because I know families that have twins. Identical Twins has nothing to do with gender. They can be two males, two females, or a male and a female. The reason they are called identical twins is due to the fact that they are conceived from one egg and one sperm.

Around one in three sets of twins is identical. This occurs because the fertilized egg divides in two while it is still a tiny collection of cells. The self-contained halves then develop into two babies, with exactly the same genetic information. Twins conceived from one egg and one sperm are called identical or 'monozygotic' (one cell) twins. The biological mechanisms that prompt the single fertilized egg to split in two remain a mystery. Approximately one quarter of identical twins are mirror images of each other, which means the right side of one child matches the left side of their twin.

***Twins account for over 90 per cent of multiple births.

***To form identical twins, one fertilized egg (ovum) splits and develops two babies with exactly the same genetic information.

***To form fraternal twins, two eggs (ova) are fertilized by two sperm and produce two genetically unique children.

Answer 7

Were you aware of the singers, "The Carpenters". Richard and Karen Carpenters. I believed they're identical twins.

I believed, I saw that show you're talking about. I always thought it's normal to have identical twins in opposite sex. It didn't occur to me otherwise until I saw your question.

Answer 8

I don't know about that. I've come to learn identical twins sharing the extact same DNA, meaning that the gender chromosome must be the same. I suppose you were watching In the Womb: Multiples, right?

Answer 9

On comcast cable on demand they are showing 2 part about mulitples in the womb.
It is something that the Discovery channal did broadcast. It was putting an interesting twist to the topic that is being discussed here.

Answer 10

well if the discovery channel says so, it must be so, then, right? never heard of identical twins of opposite sex.