# dna testing simple question **URL:** \ **Category:** Factual Questions\ **Created:** [May 28, 2015, 9:23pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072 "2015-05-28T21:23:23Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![flano1](https://avatars.discourse-cdn.com/v4/letter/f/f14d63/32.png) [@flano1](https://boards.straightdope.com/u/flano1)\ **Post date:** [May 28, 2015, 9:23pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/1 "2015-05-28T21:23:23Z")
if my dna is compared with my brother’s can our identities be differentiated? ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [May 28, 2015, 9:49pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/2 "2015-05-28T21:49:05Z")
> [@flano1](#): > > if my dna is compared with my brother’s can our identities be differentiated? Yes. They can tell that you are closely related, but they are different. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [May 28, 2015, 9:49pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/3 "2015-05-28T21:49:21Z")
Unless you’re identical twins, then yes. Identical (monozygotic) twins share the same DNA. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [May 28, 2015, 10:00pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/4 "2015-05-28T22:00:05Z")
As long as he’s not your identical twin, then yes. See [Judge Rules Man Fathered Only One Twin – Lowering the Bar](http://www.loweringthebar.net/2015/05/judge-rules-man-fathered-only-one-twin.html) for more about what happens if he \*is \*your identical twin. ETA: I may be third, but I took extra time for a cite. 🙂 ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [May 28, 2015, 10:19pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/5 "2015-05-28T22:19:38Z")
If he’s your identical twin, then it’s going to depend on how much and what part of the DNA they’re looking at. Identical twins (that is, monozygotic twins) _don’t_ always have identical DNA - but it’s \*mostly \*identical, so you have to be looking in the right place. [Identical Twins' Genes Are Not Identical - Scientific American](http://www.scientificamerican.com/article/identical-twins-genes-are-not-identical/) ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [May 28, 2015, 10:31pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/6 "2015-05-28T22:31:57Z")
Miss smarty pants. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 28, 2015, 10:50pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/7 "2015-05-28T22:50:50Z")
Although, if you’re looking at such a level of detail that you don’t look like your twin, you might not even look like you, either. There can be small differences in genes between different parts of your body, too. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [May 28, 2015, 11:09pm UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/8 "2015-05-28T23:09:48Z")
Oh, even weirder than that, just your garden variety general DNA test may not be able to tell you’re you, if you’re a chimera! [Pregnancy No Proof of Motherhood; Woman Was Her Own Twin-and the Twin Was the Mother of Her Children - Guardian Liberty Voice](http://guardianlv.com/2014/01/pregnancy-no-proof-of-motherhood-woman-was-her-own-twin-and-the-twin-was-the-mother-of-her-children/) ---
**Author:** ![flano1](https://avatars.discourse-cdn.com/v4/letter/f/f14d63/32.png) [@flano1](https://boards.straightdope.com/u/flano1)\ **Post date:** [May 29, 2015, 7:51am UTC](https://boards.straightdope.com/t/dna-testing-simple-question/721072/9 "2015-05-29T07:51:05Z")
thanks. much appreciated.