Talk:Half-identical twin

Half-identical twin is part of the WikiProject Biology, an effort to build a comprehensive and detailed guide to biology on Wikipedia. Leave messages on the WikiProject talk page.BiologyWikipedia:WikiProject BiologyTemplate:WikiProject BiologyBiology articles

Molecular Biology: MCB

	This redirect is within the scope of WikiProject Molecular Biology, a collaborative effort to improve the coverage of Molecular Biology on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.Molecular BiologyWikipedia:WikiProject Molecular BiologyTemplate:WikiProject Molecular BiologyMolecular Biology articles
	This redirect is supported by the Molecular and Cell Biology task force.

Medicine: Genetics

	Medicine portal This redirect is within the scope of WikiProject Medicine. Please visit the project page for details or ask questions at Wikipedia talk:WikiProject Medicine.MedicineWikipedia:WikiProject MedicineTemplate:WikiProject Medicinemedicine articles
	This redirect is supported by the Medical genetics task force.

Contradiction/Non-sequitur[edit]

In the introduction, the article states:

...the two individuals share the uterus and therefore obviously have the same mother...

Later, an apparent contradiction or non-sequitur is asserted:

Half twins tend not to live together since the two fathers are not usually related, and therefore sometimes half twins are not even aware of the others existence, in part due to the somewhat strained relationships between the two males.

This second sentence not only appears to be a contradiction, but patently absurd, frankly. For example, for what reason would two half-twins be inclined not to be aware of the existence of the other, at least any more so than true identical twins? Moreover, given the asserted rarity of the occurrence of half-twins, it seems unlikely that anyone would come to the conclusion that such twins in fact have two separate fathers, except in even rarer circumstances (perhaps where the two fathers are of different races). On this basis, absent any cited references to support the above-noted second sentence, I am removing it. --Ryanaxp 21:52, 26 March 2007 (UTC)[reply]

There is no contradiction between those two things. There is nothing saying that just because a mother gives birth to a child that the child will live with the mother no matter what. In addition to that, the requirement for two fathers means that one child might not be 'welcome' leading the father (and mother) of the other child to not inform the child. However, as you said it does need to be cited, so perhaps the second paragraph was added based on reasons similar to what I just pointed out, but without proof to back up the thought. 124.149.61.201 07:57, 3 April 2007 (UTC)[reply]

Single egg???[edit]

"However what confuses the matter is that the father of the two offspring must be different, and must both fertilise a single egg at exactly the same time."

This strikes me as nonsense. While I don't doubt that this can theoretically happen, it would seem to me far more likely that they would be fraternal twins, a sperm from each father fertilising a different egg. -- Smjg 01:10, 17 June 2007 (UTC)[reply]

Although unlikely, as you said "...this can... happen" and there have been examples of this happening in the past, for example Paul Yates is a notable example of this phenomenon. The fact that there are questions over this topic, is proof of the rarity of this occurrence and therefore its relevance to modern bio-mechanics.

Proof?[edit]

This whole article sounds awfully suspicious and hypothetical. Is there an actual reference article or example case we can get for this? This whole article sounds dubious. —Preceding unsigned comment added by Darthveda (talk • contribs) 22:13, 25 December 2007 (UTC)[reply]

Not only dubious, but actually undefined. The article says a lot about what half twins are not, ie they aren't polar twins. But it doesn't say what they are. It's hard to find other sources. This article, which is a blog post, says that they are the same as polar body twins (an ovum rather than embryo split). So does this one. Thayvian (talk) 23:05, 28 February 2008 (UTC)[reply]

In fact, given that the very links in the article talk about polar twinning and half twinning as the same thing, I'm re-writing the article to be about polar twinning. Thayvian (talk) 23:07, 28 February 2008 (UTC)[reply]

Done. I am not a biologist, but I've turned up the references from the literature that seem to have made it to the popular press. It is a real phenomenon but not very well studied and probably very rare. Thayvian (talk) 00:45, 29 February 2008 (UTC)[reply]

nominate for renaming?[edit]

Shouldn't this article be named Semi-identical twin? That's how the phenomenon is named on the twin article and virtually every reference I have seen on the one case where this is known to have happened. --Modi Thorson —Preceding comment was added at 17:14, 13 March 2008 (UTC)[reply]

Rewritten article[edit]

Ok you rewrote this article but it has nothing to do with the original source material. If you want to write about Semi-identical twins why did'nt you write about it on a new page rather than simply deleting a previous article? —Preceding unsigned comment added by 82.26.209.44 (talk) 11:46, 30 March 2008 (UTC)[reply]

Half-Semi Identical Twins[edit]

I am a Semi-Identical Twin. My brother and I have not understood this for our entire life. On our birth Certificate it says single ovum twins (identical) but I am female and he is male. How does this happen? Any help our direction leading would be great. Beth —Preceding unsigned comment added by 166.203.40.137 (talk) 02:18, 26 March 2009 (UTC)[reply]

Pictures?[edit]

I never really heard of a semi-identical twin or seen one. Can someone add a picture to inform other people an example of a half twin? --FamFragoso42 (talk) 01:05, 1 January 2010 (UTC)[reply]