This article is part of WikiProject Gender Studies. This WikiProject aims to improve the quality of articles dealing with gender studies and to remove systematic gender bias from Wikipedia. If you would like to participate in the project, you can choose to edit this article, or visit the project page for more information.
This article is within the scope of WikiProject Women, a collaborative effort to improve the coverage of women on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
I don't know why in humans (and manny other mammals) the female is statistically smaller, but I'd like to point that this is far from universal, and the reverse is true in lots of species. I'ts for example, very common in arachnids and, if you'd preffer a vertebrate example, in birds of prey. —Preceding unsigned comment added by 18.104.22.168 (talk) 04:57, 7 February 2010 (UTC)
It's because mammals have more immuno-active proteins than other taxa where females are usually bigger. While this is actually true for both sexes, it only presents a reproductive problem in females. In any given female, the inner part of the vagina has about as many antibodies and other immunoproteins as any other internal organ. Although these proteins are supposed to kill parasitic bacteria (that's why they evolved), they can also kill sperm, which are cells from another individual. So, given that taller women have longer vaginas based on the same general bodily proportions, if a very short man marries (or otherwise does something unethical with) a very tall woman, the sperm have a relatively longer part of their journey to be vulnerable to immunoproteins. This is the evolutionary reason for the general but not absolute relative shortness of female humans, and similar explanations could be provided for females of other mammalian species and taxa. The Mysterious El Willstro (talk) 05:27, 18 April 2010 (UTC)
Male mammals engage in violent competition for mates, territory, etc., which requires greater strength and size. 22.214.171.124 (talk) 07:11, 7 May 2016 (UTC)
None of this is an actual reason, it's only speculation as to evolutionary origins. The real reason (for simplicity, I will only speak of humans here) is that the testicles boys typically have produce much higher levels of testosterone in puberty than present in most girls (qualification is necessary to account for intersex and transgender individuals), leading (usually) to a larger body size (though with much individual variation, of course). This is demonstrated by the fact that adolescent transgender girls whose testosterone production is suppressed fail to grow as tall as they would have otherwise, while adolescent transgender boys who receive testosterone grow taller than they would have without it. (However, this is only true if hormone replacement therapy is performed in puberty. See here for details.) --Florian Blaschke (talk) 09:48, 18 September 2017 (UTC)
The size element of sexual dimorphism seems to be related to mating patterns and the levels of violence involved in reproduction. In species where there is monogamy and little male-male violence in the competition for mates (like pigeons), the two sexes tend to be similar in size (at reproductive age); where there is violent male-male competition males get larger (elephant seals). So presumably in humans it reflect some level of violence above that of pigeons but below elephant seals. I'm not sure you can call that 'speculation' because it is rooted in both evolutionary theory and in observation, even if you cannot put each and every mutation in its precise historical and environment context. 126.96.36.199 (talk) 16:24, 20 September 2019 (UTC)
"We now know that 25 per cent of the X chromosome - some 200 to 300 genes - can be uniquely expressed in one sex relative to the other. In essence, therefore, there is not one human genome, but two - male and female," Professor Willard said."
But I'm no biologist or anyone else having very much insight into definition questions etc, so I'm not going to touch this for now. I felt these are quite important scientific breakthroughs though.--Jugalator 20:33, Mar 17, 2005 (UTC)
Jugalator, I am a biologist albeit a 2nd (now going into 3rd) Year Undergraduate Biology Major. The true definition of a female, based on everything I've been taught in both high school and college, is any multicellular organism who produces 1 true gamete and 3 polar cells for each germ (ancestral) cell used in meiosis, and does so exclusively (that last part basically just means simultaneous hermaphrodites are not females). In case this needs further clarification, polar cells either lack cytoplasm entirely or have very little of it, and so they are basically plasma membranes wrapped immediately around the nuclear membrane. In most dioecious (male/female divided) species, polar cells are sterile, and are basically trash bins for extra DNA (so as to make the egg, which is the aforementioned 1 true gamete, haploid).
This is not an "outer" form in the sense of something that can be seen with a naked eye, but it is a taxonomically universal definition for the word "female."
For the record, the true definition of a male is any multicellular organism who produces 4 true gametes and 0 polar cells per germ cell used in meiosis, and does so exclusively (as thus defined, simultaneous hermaphrodites are also not males).
I digress. The sexes are defined, universally, in terms of cytoplasmic distribution. For sterile individuals, we can determine whether they should have been 4:0 or 1:3 based on the genetic or environmental sex-determining scheme of the particular species. For humans, this means the presence (male) or absence (female) of the SRY Masculation Gene, which is normally (IE in all fertile males) located on the Y Chromosome. The Mysterious El Willstro (talk) 00:00, 2 May 2010 (UTC)
The Mysterious El Willstro, I'm also a biologist, and I have never under my 6 years of university studies heard it stated that this is the universal definition of sexes, but I find it an interesting definition as I'v always thought the lack of universal definition of female/male sex to be a problem for biology. So now I wonder if you maybe could provide some sources for this definition (I tried googeling some but didn't really find any article where it were really spelled out). I also wonder if you know if those definitions deals with the fact that not all multicellular organisms function like this (in Fucus brown algae both sexes produce gamets using the 4:0 ratio, while some female flowering plants have a 2:1 ratio, and other have a 1:0 ratio) and that we also talk about female/male sex in unicellular eukaryotes that also do not follow this general pattern. Raptorialforetarsi (talk) 23:13, 8 May 2017 (UTC)
One more thing, what the heck is the part about extraterrestrials doing here? Is female extraterrestrials definitely called "women" and must be mentioned here, or is it some kind of weird joke in an encyclopedia?--Jugalator 20:35, Mar 17, 2005 (UTC)
Perhaps the wikipedia really is malecheuvenistic? Cone-spir-acy, con-spire-acy!--OleMurder 20:48, 6 February 2006 (UTC)
Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. Danski454 (talk) 11:32, 23 July 2018 (UTC)