# Are there any organs besides kidneys that we have a spare? **URL:** \ **Category:** Factual Questions\ **Created:** [February 8, 2019, 9:33pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198 "2019-02-08T21:33:38Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Zyada](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zyada/32/3028_2.png) [@Zyada](https://boards.straightdope.com/u/Zyada)\ **Post date:** [February 8, 2019, 9:33pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/1 "2019-02-08T21:33:38Z")
We have two kidneys, and I know that one can be donated to another person while you’re still alive, because my SIL donated hers to her brother when they were young. Are there any other organs that this could apply too? I know most of the other well-known organs are singleton. And I doubt anyone is going to give up an eye to help out someone else, no matter how much they are loved. Might deserve another thread, but also what impact would donating a kidney have on your life expectancy? Inspired by a reddit thread where a person had posted a photo of a car that was asking for a spare kidney for the owner’s sister. ---
**Author:** ![senoy](https://avatars.discourse-cdn.com/v4/letter/s/dbc845/32.png) [@senoy](https://boards.straightdope.com/u/senoy)\ **Post date:** [February 8, 2019, 9:43pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/2 "2019-02-08T21:43:04Z")
lungs ---
**Author:** ![Channing\_Idaho\_Banks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/channing_idaho_banks/32/250_2.png) [@Channing\_Idaho\_Banks](https://boards.straightdope.com/u/Channing_Idaho_Banks)\ **Post date:** [February 8, 2019, 9:43pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/3 "2019-02-08T21:43:37Z")
Eyes Testes ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [February 8, 2019, 9:49pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/4 "2019-02-08T21:49:10Z")
> [@Zyada](#): > > Inspired by a reddit thread where a person had posted a photo of a car that was asking for a spare kidney for the owner’s sister. Was this My Mother The Car? Seems a little presumptuous… ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [February 8, 2019, 9:57pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/5 "2019-02-08T21:57:17Z")
> [@Channing\_Idaho\_Banks](#): > > Eyes > Testes There are plenty of things we have more than one of, but I got the impression that the OP was looking for things where having more than one doesn’t confer any additional advantage except that we have a spare in case we lose one. Two eyes are better than one (better depth perception), but testes (or ovaries) might qualify. Are we restricted to organs that are donatable (using current medical technology)? ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [February 8, 2019, 9:58pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/6 "2019-02-08T21:58:08Z")
One can donate part of the [liver](http://columbiasurgery.org/liver/living-donor-liver-transplantation-faqs). Also, veins and small intestine. Though they are usually transplanted into somewhere else on the same patient rather than someone else. (Veins are used for bypass surgery, intestine can replace the esophagus if you have esophageal cancer.) Skin. ---
**Author:** ![Zyada](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zyada/32/3028_2.png) [@Zyada](https://boards.straightdope.com/u/Zyada)\ **Post date:** [February 8, 2019, 11:16pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/7 "2019-02-08T23:16:39Z")
> [@Thudlow\_Boink](#): > > There are plenty of things we have more than one of, but I got the impression that the OP was looking for things where having more than one doesn’t confer any additional advantage except that we have a spare in case we lose one. > > Two eyes are better than one (better depth perception), but testes (or ovaries) might qualify. > > Are we restricted to organs that are donatable (using current medical technology)? I was thinking more along the lines of donatable organs, especially something that you would need to get replaced if yours was damaged/diseased. Seems like ovaries and testes might qualify for being donatable, but are probably not actually needed for someone’s continued health. Although their contents are fairly common donations! ---
**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\ **Post date:** [February 8, 2019, 11:21pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/8 "2019-02-08T23:21:23Z")
Lungs come in pairs, and most people have 4 parathyroids, although that number can vary widely. We also have more bowel than we “need” (you can lose about half of it without adverse effects). Mammals also have twice as many breasts as their average litter size, which comes in handy when it comes to feeding them. I’ve definitely heard of live-liver donation (usually done between first-degree relatives) but never heard of live lung donation. I did once read about a live heart donation; IIRC, a man with cystic fibrosis needed a lung transplant, and when the lungs are transplanted, usually the heart is too because they are so interconnected. Someone in the same hospital (!) was a good match and received that man’s heart. I heard about it when I saw a news program where they met. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [February 9, 2019, 12:05am UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/9 "2019-02-09T00:05:06Z")
> [@scr4](#): > > One can donate part of the [liver](http://columbiasurgery.org/liver/living-donor-liver-transplantation-faqs). > > Also, veins and small intestine. Though they are usually transplanted into somewhere else on the same patient rather than someone else. (Veins are used for bypass surgery, intestine can replace the esophagus if you have esophageal cancer.) > > Skin. In the same (PUN ALERT!) vein, Tommy John surgery takes a tendon and moves it to the pitcher’s arm. ---
**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:** [February 9, 2019, 4:14am UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/10 "2019-02-09T04:14:01Z")
Losing one lung, kidney, or eye is still an impairment to some degree (though you can live with it). And if I understand correctly, losing one ovary would mean only one fertile cycle every two months, instead of one each month, which would also be an impairment. But a man with one testicle functions in all ways just as well as one with two, making that the only organ I know of with a fully-redundant spare. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [February 9, 2019, 6:55am UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/11 "2019-02-09T06:55:37Z")
Do fingers and toes count as “organs” for this? I recall a case where a surgeon lost a thumb and had a big toe transplanted to take its place; it worked well enough that he could still do surgery, and since it was his own toe there were no rejection issues to deal with. EDIT: Also, sometimes nerves are transplanted from one part of a person to another, generally resulting in a small numb spot somewhere low priority while the transplanted nerve fixes something important. We do have spare adrenal glands, but [apparently](https://doctor.ndtv.com/faq/is-transplantation-of-the-adrenal-glands-possible-3109) nobody is even looking into transplanting them because medicinally replacing their function is so much safer and easier than dealing with rejection. > [@nearwildheaven](#): > > I’ve definitely heard of live-liver donation (usually done between first-degree relatives) but never heard of live lung donation. I have. I recall reading of a case where each parent of a child with cystic fibrosis donated a lobe of one of their lungs. The lobes would grow with the kid, and losing a single lobe wasn’t too bad for the parents. ---
**Author:** ![Novelty\_Bobble](https://avatars.discourse-cdn.com/v4/letter/n/a3d4f5/32.png) [@Novelty\_Bobble](https://boards.straightdope.com/u/Novelty_Bobble)\ **Post date:** [February 9, 2019, 9:54am UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/12 "2019-02-09T09:54:41Z")
Nothing useful to add other than to recall that one day, some years ago, my father-in-law was telling my sister-in-law about a farmer friend of his who had a duck born with three legs. With wide eyes and mouth she took this in, churned it over for a few seconds and asked “what happened to the other one?” . . . . . [TWENTY-EIGHT YEARS OLD SHE WAS!!!](https://www.youtube.com/watch?v=gMf2MIvDjsk) ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [February 9, 2019, 2:57pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/13 "2019-02-09T14:57:46Z")
Ears. ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [February 9, 2019, 3:22pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/14 "2019-02-09T15:22:00Z")
> [@Chefguy](#): > > Ears. How would your glasses stay on? ---
**Author:** ![Eva\_Luna](https://avatars.discourse-cdn.com/v4/letter/e/e495f1/32.png) [@Eva\_Luna](https://boards.straightdope.com/u/Eva_Luna)\ **Post date:** [February 9, 2019, 3:59pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/15 "2019-02-09T15:59:43Z")
> [@scr4](#): > > Also, veins and small intestine. Though they are usually transplanted into somewhere else on the same patient rather than someone else. (Veins are used for bypass surgery, intestine can replace the esophagus if you have esophageal cancer.) Large intestine can also become bladder. ---
**Author:** ![x-ray\_vision](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/x-ray_vision/32/351_2.png) [@x-ray\_vision](https://boards.straightdope.com/u/x-ray_vision)\ **Post date:** [February 9, 2019, 4:14pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/16 "2019-02-09T16:14:41Z")
> [@Chronos](#): > > And if I understand correctly, losing one ovary would mean only one fertile cycle every two months, instead of one each month, which would also be an impairment. Not according to several cites I’ve checked such as this: > [@](#): > > In this video, Jeffrey Hunter, MD, from West Valley OB/GYN, explains losing one ovary doesn’t cause irregular periods. He says one ovary makes very little changes to a woman’s cycle. > **[Could losing one ovary cause irregular periods? | Gynecology](https://www.sharecare.com/health/gynecology/could-losing-one-ovary-cause-irregular-periods)** > > Losing one ovary, as long as the remaining ovary is healthy, should not cause irregular periods. The control of our menstrual cycles is a result of th Here’s a quick explanation of why: > [@](#): > > While the body normally alternates which ovary releases an egg at ovulation, with one ovary, an egg is still released every month. Even if the ovary is not adjacent to its original fallopian tube, as long as there is a healthy tube on the other side, it is possible for the egg to reach it and then travel to the uterus. But: > [@](#): > > However, the chances of a healthy pregnancy drop and the odds of ectopic pregnancy — where a fertilized egg implants outside the uterus — increase. > **[Tips For Conceiving with Just One Ovary | in the Stork® OTC Blog](https://storkotc.com/blog/conceiving-one-ovary/)** > > For a woman who has had one ovary removed, it’s natural to worry about fertility. Here are the key things to know about getting pregnant with a single ovary. It’s also been theorized that one ovary could result in a shorter reproductive lifespan. ---
**Author:** ![SuperAbe](https://avatars.discourse-cdn.com/v4/letter/s/f17d59/32.png) [@SuperAbe](https://boards.straightdope.com/u/SuperAbe)\ **Post date:** [February 9, 2019, 4:21pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/17 "2019-02-09T16:21:46Z")
> [@nearwildheaven](#): > > …when the lungs are transplanted, usually the heart is too because they are so interconnected. Heart-lung transplants are certainly done, but it’s usually in cases where a lung disease has also caused a cardiac issue (pulmonary hypertension leading to increased right heart pressures and eventually permanent dysfunction, for example). Single lung transplants are now pretty common in a variety of localized pulmonary disease states. They’re a little less common than bilateral transplants in CF patients, but singles are still done in some CFers (patient, hospital, and situation specific). ---
**Author:** ![Maastricht](https://avatars.discourse-cdn.com/v4/letter/m/a88e57/32.png) [@Maastricht](https://boards.straightdope.com/u/Maastricht)\ **Post date:** [February 9, 2019, 4:22pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/18 "2019-02-09T16:22:14Z")
Blood. You can donate about half a litre every few weeks. ---
**Author:** ![SuperAbe](https://avatars.discourse-cdn.com/v4/letter/s/f17d59/32.png) [@SuperAbe](https://boards.straightdope.com/u/SuperAbe)\ **Post date:** [February 9, 2019, 4:26pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/19 "2019-02-09T16:26:50Z")
> [@Chronos](#): > > And if I understand correctly, losing one ovary would mean only one fertile cycle every two months, instead of one each month, which would also be an impairment. But a man with one testicle functions in all ways just as well as one with two, making that the only organ I know of with a fully-redundant spare. Not so - losing either a single ovary or testicle has the same effect: not much. (removed long explanation since **x-ray vision** beat me to it) Tldr: reproductive organs are part of a complex and redundant feedback system. ---
**Author:** ![SigMan](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@SigMan](https://boards.straightdope.com/u/SigMan)\ **Post date:** [February 9, 2019, 6:19pm UTC](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198/20 "2019-02-09T18:19:35Z")
Brains… some people don’t use it. :rolleyes: [Next page](https://boards.straightdope.com/t/are-there-any-organs-besides-kidneys-that-we-have-a-spare/829198.md?page=2)