Why do men have nipples?

  1. Well? And do the males of other species have nipples?
     
  2. jcsd
  3. iansmith

    iansmith 1,430
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    I have seen nipple on male gorilla and chimp but i never saw nipple on a male dog or cat. The fur could in the way. The nipple is probably just a left over part from the X-chromosome. Technically mammals starts as a female in the embryo state.
     
  4. Re: Re: Why do men have nipples?

    Oh god, Gary Busey was right... "Men are just failed women at birth."

    Could you elaborate on that please?
     
  5. russ_watters

    Staff: Mentor

    Re: Re: Why do men have nipples?

    Yes, all male mammals have nipples. Your guess would be mine as well.
     
  6. Redundancy. Give everybody the same basic plumbing and let the hormones decide who gets what. The nipples that prepubescent girls have are physiologically identical to male nipples, then when the hormones kick in they develop into full grown breasts. The same general concept can be applied to why females have a clitoris and labia. If the right hormones are expressed (in the womb instead of puberty) you end up with a penis and a scrotum, respectively.
     
  7. Very, very strange. They serve no purpose at all, do they. I hadn't ever thought about it before.
     
  8. There has been a case where in a species of bat, the male can lactate to feed it's young. Now I feel that is very interesting.
    Todd
     
  9. I agree. You know there was a thread a while ago, that I can't seem to find for some reason, which talked about a few instances wherein a male human was able to breast feed his children...now that was bizarre.

    Can anyone locate that thread?
     
  10. Monique

    Monique 4,700
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    A female embryo (XX) exposed to testosterone in the womb will have male physiology.
     
  11. Hmm...I don't know how to ask this exactly, but, has that ever been linked to why some women are homosexual from birth? If so, is the opposite case (the lack of testosterone in the womb) the cause of homosexual men?
     
  12. Mentat. I seem to recall that thread.
    What I had once read was that a man who had his nipples sucked on for 20-30 minutes at a time, several times each day, began to lactate after a period several months. I believe the story was genuine, but of course I could be mistaken.


    Because men need all the erectile tissue they can get. :smile:
     
  13. Monique

    Monique 4,700
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    Very good observation! I thought I would include that in my reply, but didn't. Researchers are definately interested in looking at the effects of testosterone on the developing brain, which may cause the 'I am in the wrong body' feeling.
     
  14. I have heard that women who take steroids(male hormones), will grow a beard and moustache. With enough use there clitoris will begin to form into a small penis(oh god no!)

    If your a male, and you take birth control pills(female hormones), you will begin to develope breast and other female characteristics.
     
  15. Monique

    Monique 4,700
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    Yes, that is true: secondary sexual organs are induced by hormones too.

    There is also a disease called the Androgen Insensitivity Syndrome, where a person is born with the male (XY) chromosomes but is intersexual. 95% of intersexual people have mutations on a X-linked gene, which cause them to be insensitive to the male hormone testosterone and thus not develop the sexual organs normally in the womb (they will be infertile).
     
  16. adrenaline

    adrenaline 274
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    This brings up a nice seguay into the biology of homosexuality as Mentat brought up. Some neuroendocrine psychologists have found that women with congenital adrenal hyperplasia ( thus their in utero environment has higher testosterone exposure) have a much higher propensity for homosexuality. http://www.boskydell.com/political/outlooks.htm also http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1438641&dopt=Abstract
    http://www.findarticles.com/cf_0/m0341/2_56/66419866/p1/article.jhtml?term= the latter is a 14 page discussion of the many studies.

    Thus, is homosexual behavior dependent on the in utero hormonal milieu? Men who have complete androgen insensitivity ( internal undescended testicles, blind vaginal pouch) are in every way women and more likely to be attracted to men. By the way, these women ( because they have grown up as women until a physical exam at puberty to assess for why they are not menstruating) are very, very feminine and physically attractive. (remember, estrogen receptors have mild cross over sensitivity to testosterone and other androgens and when overstimulated by the huge doses of circulationg androgens, they exert all the estrogenic developmental patterns.) These women have to have their undescended testicles removed to eliminate the high chance of testicular cancer that occurs with undescended testicles. To show how very attractive they are there is a very famous, attractive, actress in Hollywood who is a confirmed complete androgen insensitivity syndrome (was a case study at UCLA, and Cedar Sinai Caalifornia) I won't divulge her name although it may be circulated already.

    As for the studies on male homosexual brains, we all have probably heard of simon LeVay's work on the preoptic nucleus of the anterior hypothalamus. However, I think most clinical researchers have a problem with his work due to the fact that most of his autopsy subjects were HIV infected men and we now know how profoundly the Aids virus can change and affect the brain.
     
    Last edited: Dec 4, 2003
  17. Phobos

    Phobos 2,020
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  18. chroot

    chroot 10,427
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    Blind vaginal pouch? Sounds lovely. So do the undecended testes. Oh, and I don't really think Jamie Lee Curtis is that hot. You're telling me Jamie Lee Curtis is a MAN? Chromosomally-speaking?

    - Warren
     
  19. Monique

    Monique 4,700
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    There is no uterus.
    That could very well be an urban legend :) and probably is..
     
  20. Monique

    Monique 4,700
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    Adrenaline, you are a clinician, do you know how well socially accepted intersexual people are (ie w/ androgen insensitivity disorder). What I've heard it is a taboo and doctors advice their patients to stay quiet about it, this may lead to isolation and the avoidance of sexual behaviour.

    Since JLC was married, this would argue against her being affected with the syndrome.
     
  21. adrenaline

    adrenaline 274
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    Those with complete androgen insensitivity syndromes are unaware of their disorder and have no ambiguous physical features unlike those with incomplete androgen insensitivity disorders or women with congenital adrenal hyperplasia who have enlarged clitorisis, facial hair etc. They grow up without much emotional trauma until puberty when they are not menstruating like their female XX counterparts. Outsiders are unaware that women with complete androgen insensitivity syndrome have a problem except that these women are "sterile". These women are referred to Internists, gynecologists etc. when they have not started menstruating at the age they should. Many go on to lead normal lives, seemingly heterosexual ones (get married but need to adopt children.) Their external genitalia are exactactly that of XX females so that their partners are unaware of their problems unless they are made privey about their condition. In addition, many are quite large breasted (once again, the cross over reaction by the testosterone on the estrogen receptors). Many of these genetic males do not accept the fact that they are genetic males since they have spent 13-15 yrs without any reason to doubt they are females.

    The ones who have the problems are the ones with the numerous other disorders resulting in ambiguous genitalia or virilization of secondary sexual characteristics in females. Many have to undergoe painful, reconstructive surgeries, have issues with their sexuality and sexual preferances, or need lifelong exogenous hormone replacement therapy.



    As for JLC being the one, just say that the complete androgen insensitivity syndrome women I have seen make her look comely.
     
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