Christian and Jenn: An Identical Twin Story

Three sets of twins!
Christian (left) with her twin girls
Jenn (right) with her twin boys
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Christian Fernandes recently dropped me this email:

I just stumbled across your article on identical twins, and I thought my story was worth sharing.

I’m an identical mirror twin. My twin sister Jenn and I have many mirror image traits that are pretty cool, such as the fact that she’s a lefty, I’m a righty, she’s near sighted, I’m far sighted. I have a widow’s peak, she doesn’t. And so on. We had DNA testing to confirm our zygosity back in 2006. Here’s some other unique parts to our twin story:

In 2006 I gave birth to twin girls, Georgia and Quinn.

In 2007 Jenn gave birth to twin boys, Van and Finn.

I was told throughout my pregnancy that my girls were most likely fraternal because they each had their own placenta and cord. There was a 20% chance they would be identical. But when they were born, and the days that followed, I could barely tell them apart. We did the DNA testing on my girls when they were about 9 months old, when Jenn found out she was also having twins. They knew early on that hers were identical due to all the sharing they were doing!

I wanted to forward a recent picture of the 3 sets of twins. My sister has an older daughter, and I have 2 older boys...all our of kids are genetically half siblings...kind of cool, and creepy at the same time! ;) I love being a twin, and I understand your envy! ;) Jenn is my best friend, we consider ourselves very lucky that our egg split! ;)

I would love to hear if you’ve come across another set of identical twins, who have also had identical twins. I haven’t found a story yet! Thanks for your time!

If you have a twin story, drop me an email, or post a comment on one of these threads.

Forum Thread--Conjoined Twins

Do you have any comments or stories about the conjoined twins in your life?

If so, please post in the comment section below.

Please note that your comment may be used as a stand-alone post and by posting a comment, you are granting the webmaster permission to use your content for this blog.

If you would rather email your story, need more info, and/or have an idea for a forum thread, contact the webmaster.

Definition of "Conjoined Twins" from Wikipedia:

Conjoined twins are identical twins whose bodies are joined in utero.

A rare phenomenon, the occurrence is estimated to range from 1 in 50,000 births to 1 in 100,000 births, with a somewhat higher incidence in Southwest Asia and Africa.

Approximately half are stillborn, and a smaller fraction of pairs born alive have abnormalities incompatible with life. The overall survival rate for conjoined twins is approximately 25%. The condition is more frequently found among females, with a ratio of 3:1.

Two contradicting theories exist to explain the origins of conjoined twins. The older theory is fission, in which the fertilized egg splits partially. The second and more generally accepted theory is fusion, in which a fertilized egg completely separates, but stem cells (which search for similar cells) find like-stem cells on the other twin and fuse the twins together. Conjoined twins share a single common chorion, placenta, and amniotic sac, although these characteristics are not exclusive to conjoined twins as there are some monozygotic but non-conjoined twins that also share these structures in utero.

The most famous pair of conjoined twins was Chang and Eng Bunker (Thai: อิน-จัน, In-Chan) (1811–1874), Thai brothers born in Siam, now Thailand. They traveled with P.T. Barnum's circus for many years and were billed as the Siamese Twins.

Chang and Eng were joined by a band of flesh, cartilage, and their fused livers at the torso. In modern times, they could have been easily separated. Due to the brothers' fame and the rarity of the condition, the term "Siamese twins" came to be used [for many years] as a synonym for conjoined twins [but is now considered to be a pejorative term].

Forum Thread--Half-identical or Semi-identical Twins

Do you have any comments or stories about the half-identical twins in your life?

If so, please post in the comment section below.

Please note that your comment may be used as a stand-alone post and by posting a comment, you are granting the webmaster permission to use your content for this blog.

If you would rather email your story, need more info, and/or have an idea for a forum thread, contact the webmaster.

Definition of "Half-identical Twins" from Wikipedia:

Half-identical or semi-identical twins (also referred to as "half twins") are the result of a very rare form of twinning in which the twins inherit exactly the same genes from their mother but different genes from their father.

Although examples of half-identical twins have been found, the exact mechanism of their conception is not well-understood, but could theoretically occur in polar body twinning where sperm cells fertilize both the ovum and the second polar body.

This situation is not the same as the common form of fraternal twinning, in which two genetically different ova are fertilized by two genetically different sperm. In this case, the ova are genetically identical.

There are two mechanisms by which this might happen:

Polar twins (or "polar body twins"), where two sperm fertilize an ovum, one of the two fertilizing a polar body; or where an ovum splits into identical copies, one containing a polar body, prior to fertilization, allowing it to be fertilized by two different sperm.

Sesquizygotic twins, where two sperm fertilize the one ovum, forming a triploid, and then splitting.

A 1981 study of a deceased triploid XXX twin fetus without a heart showed that although its fetal development suggested that it was an identical twin, as it shared a placenta with its healthy twin, tests revealed that it was likely a polar body twin.

The authors were unable to predict whether a healthy fetus could result from a polar body twinning. In 2003 a study argued that many cases of triploidity arise from semi-identical twinning.

In 2007, a study reported a case of a pair of living twins, one a hermaphrodite and one a phenotypical male. The twins were both found to be chimeras and to share all of their maternal DNA but only half of their father's DNA. The exact mechanism of fertilization could not be determined but the study stated that it was unlikely to be a case of polar body twinning.

About This "Hybrid" Forum on the Blogger Platform

I'll be the first to admit this:

A Blogger forum does not offer an ideal platform for spontaneity; it has its technical limitations--for example, if you want to edit or delete your comments, you cannot, and you cannot start threads or post articles, unless you have been invited and been accepted as a member of this blog.

However, I have been an admin on a standard forum, and I must tell you: it was a nightmare, one that I do not wish to repeat (trolls, spammers, porners, etc.) so I thought I would try using Blogger, which now offers a lot of cool widgets and templates. And as I have become much more adept with the Blogger format, the site will be fairly easy to navigate.

It also offers me more control over what gets posted on this site, which is a very specialized one having to do with twins and practical issues surrounding twinning. In other words, this is not a political site, nor is it an "anything goes" site.

As admin/owner, I get to decide what is appropriate for posting.

Having said this, I tend not to have a twitchy finger when it comes to the delete button. I don't mind controversy and disagreement among commentators, but I do expect two things: basically staying on topic (twins!) and being respectful of others.

What will be deleted from this site:

--Comments with outside links.

Sorry, but I have no way of knowing where that link will take readers.

--Off topic comments

--Advertising and general spam

--Hate speech

--Name calling

--Bad language

--Accusations (false and/or unproven)

--Pornography

Two final items:

1. Forum threads will not contain any illustrations. On the other hand, regular blog posts may offer photographs and artwork.

2. You must be signed into your blogger/gmail account in order to post a comment on this blog.

Happy commenting!

Forum Thread: Monozygotic ("Identical") Twins

Do you have any comments or stories about the identical twins in your life? If so please post in the comment section below. Please note that your comment may be used as a stand-alone post and by posting a comment, you are granting the webmaster permission to use your content for this blog.

If you would rather email your story, need more info, and/or have an idea for a forum thread, contact the webmaster.

Definition of "Identical Twin" from Wikipedia:

Monozygotic ("identical") twins Monozygotic (MZ) occur when a single egg is fertilized to form one zygote (hence, "monozygotic") which then divides into two separate embryos.

Mechanism

Regarding spontaneous or natural monozygotic twinning, a recent theory posits that monozygotic twins are formed after a blastocyst essentially collapses, splitting the progenitor cells (those that contain the body's fundamental genetic material) in half, leaving the same genetic material divided in two on opposite sides of the embryo.

Eventually, two separate fetuses develop. Spontaneous division of the zygote into two embryos is not considered to be a hereditary trait, but rather a spontaneous or random event.

Monozygotic twins may also be created artificially by embryo splitting. It can be used as an expansion of IVF to increase the number of available embryos for embryo transfer.

Incidence

Monozygotic twinning occurs in birthing at a rate of about three in every 1000 deliveries worldwide.

The likelihood of a single fertilization resulting in monozygotic twins is uniformly distributed in all populations around the world. This is in marked contrast to dizygotic twinning, which ranges from about six per thousand births in Japan (almost similar to the rate of identical twins, which is around 4–5) to 15 and more per thousand in some parts of India[16] and up to over 20 in some Central African countries. The exact cause for the splitting of a zygote or embryo is unknown.

In-vitro fertilization techniques are more likely to create dizygotic [fraternal] twins. Only about three pairs of twins per 1,000 deliveries occur as a result of natural conception, while for IVF deliveries, there are nearly 21 pairs of twins for every 1,000.

Genetic and epigenetic similarity

Monozygotic twins are genetically identical and they are always the same sex unless there has been a mutation during development. The children of monozygotic twins test as half-siblings (or full siblings, if monozygotic twin sisters reproduce with monozygotic twin brothers), rather than first cousins. On rare occasions, monozygotic twins may express different phenotypes, normally due to an environmental factor or the deactivation of different X chromosomes in female monozygotic twins, and in some extremely rare cases, due to aneuploidy, twins may express different sexual phenotypes, normally from an XXY Klinefelter's syndrome zygote splitting unevenly.

Monozygotic twins actually have only nearly identical DNA, and differing environmental influences throughout their lives affect which genes are switched on or off. This is called epigenetic modification.

A study of 80 pairs of human twins ranging in age from three to 74 showed that the youngest twins have relatively few epigenetic differences. The number of epigenetic differences between "identical" twins increases with age. Fifty-year-old twins had over three times the epigenetic difference of three-year-old twins. Twins who had spent their lives apart (such as those adopted by two different sets of parents at birth) had the greatest difference. However, certain characteristics become more alike as twins age, such as IQ and personality. This phenomenon illustrates the influence of genetics in many aspects of human characteristics and behavior.

Phenotype similarity

Contrary to common opinion, monozygotic twins are not always of the same phenotypical sex. There have been described cases where monozygocity resulted in 46,XO (i.e. female with Turner syndrome) and 46,XY (i.e. male). This is thought to be due to unequal distribution of zygotic protoplasm. However, as a rule, traits and physical appearances of MZ twins are very similar.

Monozygotic twins do generally look alike, although they do not have the same fingerprints (which are environmental as well as genetic). As they mature, monozygotic twins often look less alike or more alike because of lifestyle choices or external influences.

Forum Thread: Fraternal/Sororal (Dizygotic) Twins

Do you have any comments or stories about the fraternal twins in your life? If so please post in the comment section below.

Please note that your comment may be used as a stand-alone post and by posting a comment, you are granting the webmaster permission to use your content for this blog.

If you would rather email your story, need more info, and/or have an idea for a forum thread, contact the webmaster.

Definition of "Fraternal Twin" from Wikipedia:

Fraternal or dizygotic (DZ) twins (also referred to as "non-identical twins," "dissimilar twins," "biovular twins," and, in cases of females, sororal twins) usually occur when two fertilized egg are implanted in the uterus wall at the same time. When two eggs are independently fertilized by two different sperm cells, fraternal twins result. The two eggs, or ova, form two zygotes; hence, the terms dizygotic and biovular.

Dizygotic twins, like any other siblings, have an extremely small chance of having the same chromosome profile. Like any other siblings, dizygotic twins may look similar, particularly given that they are the same age. However, dizygotic twins may also look very different from each other. They may be of different sexes or the same sex. The same holds true for brothers and sisters from the same parents, meaning that fraternal and/or sororal twins are simply siblings who happen to be the same age.

Studies show that there is a genetic basis for dizygotic twinning. However, it is only their mother that has any effect on the chances of having such twins; there is no known mechanism for a father to cause the release of more than one ovum.

Dizygotic twinning ranges from six per thousand births in Japan (similar to the rate of monozygotic twins) to 14 and more per thousand in some African countries.

Dizygotic twins are also more common for older mothers, with twinning rates doubling in mothers over the age of 35. With the advent of technologies and techniques to assist women in getting pregnant, the rate of fraternals has increased markedly.

About Douuble, a Website About Twins

To have joy one must share it. Happiness was born a twin.

--Lord Byron

This site focuses on twins of all ages, friends and relatives of twins, and parents of twins.

It is part blog and part forum, albeit a limited forum platform.

If you have a blogger account, you may post in the comment section, from where I will eventually invite posters to be active members of this blog, a space to post text/images and start topic threads.

I envision a site where members of this blog will actively post their own twin stories and photos.

I am not a twin myself, although I have always been drawn to and fascinated by twins.

Indeed, I refer to myself as a "twin magnet," usually meeting only one-half of the twin duo. For example, my former graduate advisor at Goddard College is a twin, and I have had numerous students who were twins.

And now, for the first time in my life, I have twin relatives: Owen and Henry, who will be one year old in April 2012.

I often wonder if I did have a twin in utero, for I have always felt a missing something (someone?) in my life.

The background and banner for this blog have been created from my own baby picture. My "alter ego," through the miracle of Adobe, is just my own mirror image, and, perhaps, a lot of wishful thinking.

I am writing a novel about separated twin sisters who, at 50, discover each other for the first time. Because I have never been a twin, I have had to conduct a lot of research.

If you are interested in becoming a member of this blog, please email me a sample of your writing (pasted in the body of your email) and an attached jpeg image of yourself and (if applicable) of your twin.

You do not have to be a twin to be a member--just a good writer who is deeply interested in the phenomenon of twinning.