# What causes a third nipple? **URL:** \ **Category:** Factual Questions\ **Created:** [October 20, 2003, 4:30pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533 "2003-10-20T16:30:33Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![mrbuddylee](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@mrbuddylee](https://boards.straightdope.com/u/mrbuddylee)\ **Post date:** [October 20, 2003, 4:30pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/1 "2003-10-20T16:30:33Z")
I guess it’s a birth defect, but I don’t know. Seems like I’ve heard that some of them (on women) can actually produce milk, but most are just there for looks. If a mother drinks alcohol or smokes, would the baby be more likely to have one of these? I’m just wondering, I have one, and it’s not one of those things that’s talked about that much, and I haven’t found a whole lot about the mysterious things. I know that my mom smoked while she was pregnant (Carltons she said) so could that be the cause? Think I can sue the tobacco companies and get some money? 🙂 Anyone know what they’re around for and why they’re more common than a third testicle or third arm or something (If they are in fact more common, I don’t really know). And along those same lines, why don’t you hear about kids born with extra internal organs, only external? I guess it does happen, it’s just not as easy to see so to speak. Thanks! ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [October 20, 2003, 4:37pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/2 "2003-10-20T16:37:35Z")
Is this inheritted? I seem to recall there are people who have six fingers and it is inheritted. ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [October 20, 2003, 5:11pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/3 "2003-10-20T17:11:44Z")
I’ve got **4** nipples, but no one else in my family has more than 2. There’s a thread in ‘In My Humble Opinion’ that I started, titled ‘How Many Nipples Do YOU Have?’, and many here responded that they have 3 or 4 nipples. I don’t think it’s inheritted, but I suppose it could be in some cases. My mother didn’t smoke, either. ---
**Author:** ![mrbuddylee](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@mrbuddylee](https://boards.straightdope.com/u/mrbuddylee)\ **Post date:** [October 20, 2003, 5:29pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/4 "2003-10-20T17:29:54Z")
4? Wow! Congrats! 🙂 I don’t think it’s inherited, but I don’t know. I was adopted, so coming up with a detailed family history is hard to do. So, do you think it’s more common that something like a 3rd testicle or 3rd ovary? ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [October 20, 2003, 5:34pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/5 "2003-10-20T17:34:00Z")
Yes, it can be genetically passed on. I knew two brothers and thier father that had them. Very small, but still visible. The actual term is **supernumerary, nipple** as opposed to vestigial. Now you have something to Google. I think Houdini had one, and Chandler on “Friends” claimed to have one too. ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [October 20, 2003, 5:44pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/6 "2003-10-20T17:44:18Z")
You ever see nipples on male dogs? I think it’s related to that. FWIW, I have vestigial nipples - on the right side of my chest, there’s a mole about the height of my sternum, set in a little closer to the middle than my real nipple. Then there’s a mole on the left side, just left of my navel. When I was a teenager and some hair started appearing on my chest, first around my nipples, hair also grew a little thicker around these vestigial nipples, on both the left and right sides. Once the hair had come in all the way, there was no apparent difference, so it’s much harder to tell now. They just look like two ordinary moles. ---
**Author:** ![bayonet1976](https://avatars.discourse-cdn.com/v4/letter/b/77aa72/32.png) [@bayonet1976](https://boards.straightdope.com/u/bayonet1976)\ **Post date:** [October 20, 2003, 5:57pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/7 "2003-10-20T17:57:26Z")
They can be inherited. My grandfather had one, and so do I. According to family lore it skips a generation every time, but only on the male side of the family. ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [October 20, 2003, 6:03pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/8 "2003-10-20T18:03:23Z")
Here’s a study- [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list\_uids=83305656](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=83305656) “_The incidence of this anomaly was one per 40 or 25 per 1,000 live births. Association of other congenital abnormalities with SNNs was not found_” ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [October 20, 2003, 6:11pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/9 "2003-10-20T18:11:39Z")
…and here’s a related thread- [http://boards.straightdope.com/sdmb/showthread.php?threadid=140533&highlight=Nipples](http://boards.straightdope.com/sdmb/showthread.php?threadid=140533&highlight=Nipples) ---
**Author:** ![mrbuddylee](https://avatars.discourse-cdn.com/v4/letter/m/51bf81/32.png) [@mrbuddylee](https://boards.straightdope.com/u/mrbuddylee)\ **Post date:** [October 20, 2003, 8:19pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/10 "2003-10-20T20:19:28Z")
Wow, 1 per 40??? Wow, I wonder if people I know are just in denial about it or they just don’t tell people because of the weird social aspect. Still, anyone know what causes them and why they’re so common? ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [October 20, 2003, 8:46pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/11 "2003-10-20T20:46:57Z")
> [@](#): > > [Cecil in the “Why do men have nipples?” column](http://www.straightdope.com/classics/a1_093.html) > Human nipples appear in the third or fourth week of development, well before the sex characteristics. (The sex hormones start to assert themselves at seven weeks.) As many as seven pairs of nipples are arranged along either side of a “milk line,” a ridge of skin that runs from the upper chest to the navel. > > Normally only one pair amounts to anything, but on about one baby in a hundred you can detect some vestige of the other ones, usually on the order of a freckle. ---
**Author:** ![foostav](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@foostav](https://boards.straightdope.com/u/foostav)\ **Post date:** [October 20, 2003, 9:42pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/12 "2003-10-20T21:42:17Z")
Sorry, it’s pretty obvious that you have been marked by Satan. ☹ ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [October 20, 2003, 10:57pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/13 "2003-10-20T22:57:31Z")
> [@](#): > > \*Originally posted by mrbuddylee \* > **Wow, 1 per 40??? Wow, I wonder if people I know are just in denial about it or they just don’t tell people because of the weird social aspect.** It’s possible they don’t know they have them. I can see where the third and fourth nipple are if I look _really_ closely. I doubt if anyone else would ever notice. This could also explain the difference between the 1/100 and 2.5/100 figures quoted for incidence - maybe it depends how hard you look. ---
**Author:** ![Walloon](https://avatars.discourse-cdn.com/v4/letter/w/fbc32d/32.png) [@Walloon](https://boards.straightdope.com/u/Walloon)\ **Post date:** [October 21, 2003, 12:06am UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/14 "2003-10-21T00:06:55Z")
Art thou a witch? ---
**Author:** ![ricepad](https://avatars.discourse-cdn.com/v4/letter/r/b38774/32.png) [@ricepad](https://boards.straightdope.com/u/ricepad)\ **Post date:** [October 21, 2003, 5:25am UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/15 "2003-10-21T05:25:35Z")
I have three, and my dad says that my mom has three, also. My third nipple is inverted, so it looks like it might be a scar. When I was in Jr. Hi, I got a lot of mileage by telling everybody I got it in a knife fight… ---
**Author:** ![ricepad](https://avatars.discourse-cdn.com/v4/letter/r/b38774/32.png) [@ricepad](https://boards.straightdope.com/u/ricepad)\ **Post date:** [October 21, 2003, 5:37am UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/16 "2003-10-21T05:37:30Z")
> [@](#): > > \*Originally posted by Walloon \* > \*\*Art thou a witch? \*\* I weigh more than a duck… ---
**Author:** ![xvxdarkknightxvx](https://avatars.discourse-cdn.com/v4/letter/x/34f0e0/32.png) [@xvxdarkknightxvx](https://boards.straightdope.com/u/xvxdarkknightxvx)\ **Post date:** [October 21, 2003, 6:28am UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/17 "2003-10-21T06:28:04Z")
Heeeey. Guess what! I have this mole under my armpit that I always thought looked a little funny and was a little too squishy and big. Well, I just further inspected it, and I’m pretty sure it’s a mini-nipple. It looks like a small nipple, but it doesn’t have the darker skin color surrounding it, just the tip. Thanks for listening! ---
**Author:** ![ricepad](https://avatars.discourse-cdn.com/v4/letter/r/b38774/32.png) [@ricepad](https://boards.straightdope.com/u/ricepad)\ **Post date:** [October 21, 2003, 8:14am UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/18 "2003-10-21T08:14:31Z")
> [@](#): > > \*Originally posted by xvxdarkknightxvx \* > \*\*Heeeey. Guess what! I have this mole under my armpit that I always thought looked a little funny and was a little too squishy and big. Well, I just further inspected it, and I’m pretty sure it’s a mini-nipple. It looks like a small nipple, but it doesn’t have the darker skin color surrounding it, just the tip. > > Thanks for listening! \*\* Sorry, but that ain’t a nipple…supernumeraries are always found on a line between your ‘normal’ nipple and your pubic symphesis…it’s called the “milk line”. ---
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [October 21, 2003, 2:40pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/19 "2003-10-21T14:40:24Z")
It could still be a supernumerary nipple, **ricepad**. In a minority of cases, the extra nipple is locate _above_ the other nipples. Here’s a picture of a guy with a nipple on the back of his shoulder (WARNING: link may not be appropriate for work)- [http://www.emedicine.com/derm/topic735.htm](http://www.emedicine.com/derm/topic735.htm) ---
**Author:** ![even\_sven](https://avatars.discourse-cdn.com/v4/letter/e/dfb087/32.png) [@even\_sven](https://boards.straightdope.com/u/even_sven)\ **Post date:** [October 21, 2003, 5:44pm UTC](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533/20 "2003-10-21T17:44:26Z")
I know two people with third nipples. One of them is a little less developed on one side of his body. That side grows less hair, etc. It’s also the side of the third nipple. So maybe that is related. [Next page](https://boards.straightdope.com/t/what-causes-a-third-nipple/208533.md?page=2)