Are these twins twins?

[FriedChicken]

Imagine this. Some woman takes fertility drugs while having sex with multiple persons, and somehow it happens that 2 eggs get fertilized at the same time from 2 different men. Will the resulting children be considered twins?

[ecoli]

This is an interesting question and it depends on what definition you go by.

 

http://www.google.com/search?hs=jyH&hl=en&lr=&safe=off&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&q=define%3A+fraternal+twins&btnG=Search

 

According to defintion 1, I wouldn't think so. but the second and third defintion seem to fit.

[tejaswini]

no, since clearly their genome would be quite different from each other.although the twins donot have an exactly similar kind of genetic makeup but most of it matches.

[ecoli]

no, since clearly their genome would be quite different from each other.although the twins donot have an exactly similar kind of genetic makeup but most of it matches.

 

Most of the definitions say "share a womb." Say nothing about their genome.

[DaveC426913]

Yes, they are still twins. My wife works in the industry, specifically with multiples. There is a whole rainbow of twin types, including two embryos by two different fathers.

[Genecks]

I'm curious as to how the fathers' DNA would have divided among the eggs.

[Dak]

evenly. one father's sperm fertilises one egg, the others the other.

 

iirc, whilst some sperm goes off looking for the egg, some sperm set up a 'blockade' and will kill any sperm from another man that they find.

[Glider]

Only one sperm can fertilize any egg. Once a sperm has penetrated the ootyte membrane, the properties change making it impenetrable to any other sperm.

[Genecks]

I agree, Glider.

 

I'm trying to understand what DaveC426913 is talking about. The only way I see two children coming out as twins would be if the DNA from two sperm seperated, parted away, and one strand from each went into each egg.

 

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[Glider]

Not really. There are two basic types of twins: Monozygotic (MZ) twins come from a single egg fertilized by one sperm. The resulting blastocyst separates to form two separeate embryos sharing 100% of their DNA. This results in identical twins.

 

Dizigotic (DZ) twins come from two eggs fertilized by two different sperm (usually at the same time and by the same man). If these twins come from the same father then they will share 50% of their DNA.

 

However, as DZ twins form from two separate eggs fertilized by two separate sperm, ther is nothing to say that two separate eggs can't be fertilized by two separate sperm from two separate men as long as the woman has intercourse with the second man before the first blatocyst embeds in the uterine lining. As soon as this happens, hormones are released that induce changes in the lining to prevent further blastocysts embedding. This is the principle by which many prophylactic pills work. They convince the body it's pregnant which stops any fetilised egg embedding in the uterine deciduum.

 

The time window is actually fairly generous. Conception hardly ever takes place at the time of intercourse. It can take up to a day or so for the sperm to reach and fertilize an egg. Most women actually conceive whilst shopping.

[ecoli]

Most women actually conceive whilst shopping.

 

Ouch... I just heard one thousand feminist scream bloody murder at you.

[bascule]

Holy memes, batman!

 

https://jamshaid.wordpress.com/2006/05/04/astonishing-twins/

 

 

 

http://msnbc.msn.com/id/15447465/

 

 

http://www.geneticsandhealth.com/2006/10/21/twins-with-different-skin-color-genes/

 

 

Guess this happens more often that one would think...

[Dak]

the second from bottom both have the same father.

 

i remember another case like that in the uk: the mother was white, the father black, and the twins were one white, one black.

[Glider]

Ouch... I just heard one thousand feminist scream bloody murder at you.

Yeah, but feminists shop too, as do men, it's just that they're less likely to conceive whilst doing so. Men that is, not feminists. Well... no, forget it.