# Is NASA's Kelly twin study of people living in Space flawed? **URL:** \ **Category:** Factual Questions\ **Created:** [April 12, 2019, 4:34pm UTC](https://boards.straightdope.com/t/is-nasas-kelly-twin-study-of-people-living-in-space-flawed/832442 "2019-04-12T16:34:01Z")\ **Posts on this page:** 4\ **Page:** 2
**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:** [April 12, 2019, 7:39pm UTC](https://boards.straightdope.com/t/is-nasas-kelly-twin-study-of-people-living-in-space-flawed/832442/21 "2019-04-12T19:39:03Z")
> [@](#): > > Quoth **bonzer** : > > Speaking as an identical twin who has a longstanding scepticism about “twin studies”… Don’t you mean “speaking as an identical twi”? Because there’s only one of you. 😉 ---
**Author:** ![simster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/simster/32/1047_2.png) [@simster](https://boards.straightdope.com/u/simster)\ **Post date:** [April 12, 2019, 7:46pm UTC](https://boards.straightdope.com/t/is-nasas-kelly-twin-study-of-people-living-in-space-flawed/832442/22 "2019-04-12T19:46:53Z")
> [@Jasmine](#): > > Well, repetition is an important part of the scientific method. Repeating an experiment numerous times and compiling results from all of those experiments goes a long way in ruling out chance as a variable. In this particular instance, we have one set of twins and that’s it. Perhaps some of those changes/variances can be attributed to him as an individual. There’s no way of knowing for sure unless we repeat the experiments with, for example, 100 sets of twins. You can also compare the physiological changes of any non-twin - its just now, they have atleast 1 example of ‘before and after’ with a ‘before’ still available. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [April 12, 2019, 9:45pm UTC](https://boards.straightdope.com/t/is-nasas-kelly-twin-study-of-people-living-in-space-flawed/832442/23 "2019-04-12T21:45:55Z")
> [@BubbaDog](#): > > So, are you’re saying my statement is wrong or are you just arguing the term? > > edit: my reply sounds snarky (unintentional) I actually want to know if my logic is wrong I don’t think you’re wrong, but I don’t think there’s anything wrong with “twins study.” I’m trying to figure out similar instances that are more analogous. Like “couple therapy” and “couples therapy” (though that can also be “couples’ therapy.”) The latter sounds a bit more correct to me than the former. Looking at Google ngram viewer, the latter is much more common, though sometimes rendered as a possessive (i.e. “couples’ therapy” or “couple’s therapy.”) When I put the quote marks on both phrases (which I hope excludes the possessive usage), “couples therapy” is still more commonly used. I’m thinking about why this may be. There’s something about treating “twin” separately and “twins” as a group to me that makes it sound to me like it’s not perfectly analogous with the dog-dogs example. Googling, the phrase clearly goes both ways. Here’s [“Twins Research”](https://www.sri.com/research-development/twins-research) from SRI International, an American non-profit research group. MSU has [Twin Studies](https://msutwinstudies.com/why-twin-studies). NASA has [Twins study](https://www.nasa.gov/twins-study/about). Wall Street Journal says [twins study](https://www.wsj.com/articles/a-twins-study-shows-adhd-isnt-just-genetic-1493996284). Another [WSJ article](https://www.wsj.com/articles/SB122047003725696177) (you have to dig into the text) says “The political scientists say it’s not enough to see a pattern in a twin study or even to identify a suspect gene.” That’s why I said it’s a separate issue, because that part of it is a little more nuanced and subject to a good bit of discussion, as opposed to the statement that “twin” is a plural already, or that it is a collective noun. It is neither. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [April 12, 2019, 9:53pm UTC](https://boards.straightdope.com/t/is-nasas-kelly-twin-study-of-people-living-in-space-flawed/832442/24 "2019-04-12T21:53:46Z")
> [@aceplace57](#): > > Ok, I must of been absent that day in English. 😉 You must’ve been absent for longer than that. Did you somehow miss all references to the Olsen Twin_s_ during the 1990s? Did you call Mary-Kate and Ashley the Olsen Twin? Or the Spearmint Twins in the 1960s? Or so many sitcoms in the 1980s where a character brags about “dating twins”? That is quite hard to believe. [Previous page](https://boards.straightdope.com/t/is-nasas-kelly-twin-study-of-people-living-in-space-flawed/832442.md?page=1)