The male penis and scrotum are external, whereas the female sex organs are placed "inside" the body. As females have the bladder, rectum etc. just like males, does this mean overall females have a larger volume of organs? Is this why females have wider hips — because the male penis and scrotum are external appendages just like female breasts?

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    $\begingroup$ The ovaries and uterus are pretty small except for the uterus during pregnancy. Just for comparison, think of how your intestines take up a significant fraction of the abdominal cavity, but the actual space they take up completely depends on how much food etc is in there - that variation from hour to hour is going to be a lot more than the volume of the female reproductive organs when not pregnant. $\endgroup$
    – Bryan Krause
    Dec 11, 2016 at 17:47
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    $\begingroup$ @BryanKrause I guess you could extend your comment (and use keywords like phenotypic plasticity) into an answer if you want to. $\endgroup$
    – Remi.b
    Dec 11, 2016 at 17:52
  • $\begingroup$ @Remi.b Not really my area besides a familiarity with abdominal anatomy necessary to pluck arteries out of an animal model, so I'll let someone else take a stab at it, just hoping to redirect the question asker a bit: probably the more interesting question to think about are the female specializations for pregnancy and delivery (humans and animals), rather than space for the organs generally. $\endgroup$
    – Bryan Krause
    Dec 11, 2016 at 18:01
  • $\begingroup$ You are asking multiple questions here. I would suggest that you restrict your question to the pelvic region, as your question title says. Each organ would have sex-based differences. We cannot cover all that in a single post. $\endgroup$
    Dec 12, 2016 at 5:40
  • $\begingroup$ Oh cool @WYSIWYG I'll make the second paragraph into a separate question. $\endgroup$
    – Aditya P
    Dec 12, 2016 at 8:39

2 Answers 2


Wider hips in females is not contributed because of large volume of organs.

Broadening of the hip bones happens as a feature of the female pubertal process, and estrogens (the overwhelming sex hormones in females) cause an enlarging of the pelvis as a piece of sexual separation. Consequently females for the most part have more extensive hips, allowing labor.

However, I found this article from International Business Times that states >>

Women have not evolved wider pelvises despite it being difficult and dangerous to give birth – yet they may have developed some physical features that help during labour.

Barbara Fischer, from the University of Oslo, has found a link between pelvis shape and statue and head circumference of both baby and mother.

There was, however, no sufficient evidence to back this article, but it is quite an interesting approach otherwise.

Males are not needed to have any extra organs, but females have just more space in the pelvis region. That space can be linked to idea of uterus expanding to hold the fetus during gestation as mentioned by @BryanKrause.

  • $\begingroup$ the article is a poor understanding of a study on the size of the birth canal portion of the pelvis, the pelvis as a whole is still wider. a big red flag is it is the an article in business times about evolutionary biology. $\endgroup$
    – John
    Dec 27, 2022 at 2:11

mostly nothing, males have narrower pelvises. The prostate, seminal vesicle, and basal anchorage of the penis do take up some space.


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