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Are males taller than females in humans?


Is there any scientific evidence that in humans males are taller than females? And if so, what is the reason that they are taller (please include genes or hormones that accounts for human growth and how they are affected in males and females)?


Are males taller than females?

Best data I could find come from the Statistical Abstract of the United States (1999) > Section 3. Here is a table reporting the percentage of the male and female population which height is lower than a given threshold

Note that this data collection was done among students in US universities and is therefore not representative of the whole world or even the whole country.

Does height follow a bimodal distribution?

A difference in height between males and females is often used as a classical example in introductory statistic class to exemplify a bimodal distribution as seen in this picture

and on these (a priori fake) data

However, Schilling et al. 2002 argued that while the difference in mean height between the sexes is real, this difference is too small relative to the variance in height within each sex to be clearly depicted on a graph.

Note that I found this non-peer-reviewed paper which shows real data that display a truly bimodal distribution of height.

Genetics of height

The questionwhy are they taller?is very broad. I will just focus to give you some hints about the genetics of height in humans. First, you want to make sure you understand the concept of heritability.

Evoy and Vissher 2009 report a heritability coefficient of 0.8. This estimate is impressively high - only a few phenotypic traits have such high heritability. They also review articles discussing that 50 loci are correlated with variation in height (actually, today, more than 500 loci are known to contribute to height, see the link in AlexDeLarge's comment to this answer). However, these loci are not sufficient to explain the whole heritability observed (common missing heritability issue). Yang et al. 2010 provide evidence that the remaining heritability is due to incomplete linkage disequilibrium between causal variants and loci of weak effects. In short, height is a highly polygenic trait.

Related post

You should have a look at Is there a genetic reason explaining the difference of the height of male and female? for more information.


Are Men Physically Stronger Than Women?

What exactly do people mean when they throw this statement around as though it is an indisputable fact of existence? Are these words truly limited to the female body, or do they extend to the degradation of the female identity as a whole, encouraged as it is by a history of oppression?

Usually when making this argument, people mention that scientific studies show this hypothesis to be accurate, so let's delve right into it. What does science tell us?

Right, then. Now, let's see if you can tell me what these two little “factoids” have in common.

It seems that neither of them tell us why it is that these statistics have come to be what they are. They fail to answer questions such as, what is the cause of these differences? Are they in any way conditioned into existence by the environment in which these individuals grow up?

Clearly, there seem to be anatomical differences between what is termed “biological females” and “biological males.” But are these differences accentuated – exaggerated, even – by the way in which our society is organized?

The first statement delineated as “fact,” tells us that “biological men” tend to have particular characteristics that, for arbitrary reasons, have come to be the qualities that define physical strength. These qualities, however – as clearly stated – are supposedly incited by testosterone. Before we even question that claim, let us for a moment assume it is true.

The question remains: what exactly creates high levels of testosterone? Testosterone can be found in every human body. In biological males, it is produced by the testes. Doubtlessly, this could contribute to increased numbers. But could it really account for the overbearing difference that exists (in testosterone levels) between the binary sexes? Has it not, in fact, been shown that high levels of aggressiveness, libido (sex drive) and even confidence are directly related to said levels?

From the dawn of civilization, the majority of humans encouraged the aforementioned qualities in biological males. They were pushed to do dangerous tasks (like hunting animals for food), to be aggressive toward intruders, to have as many sexual partners as possible, etc. In today's society, the previous expectations have merely been transformed into other, very similar roles -- males are now expected to be confident and courageous, to refrain from showing emotions (unless it's anger), to be proud of their “physical prowess,” to be encouraged on their sexual promiscuity, among other things.

All the behavioral tendencies I just mentioned hold one thing in common: they increase levels of testosterone. It is curious how the very thing that is assumed to be the cause of increased physical strength in biological males (i.e. testosterone) is linked to exactly the sort of behavior that is encouraged in (and often forced upon) them – the same sort of behavior that increases these very particular hormonal levels.

But let us stop assuming the truthfulness of the initial claim that testosterone is entirely responsible for these differences. What about all other factors, such as those related to outside influence? Like males being told from the moment they can speak (and even beforehand) that they are capable of physical greatness, for example? What about how females are told in every way that they are lesser – that no matter what they do, they can never achieve the physical strength of males because males somehow are inherently superior in this sense? Is it not harder for someone to achieve a brawny complexion when they, say, are made to do less work in gym class every day? Or when they are told that playing sports and exercising should not be their main preoccupation – that other things matter more? What if the opposite is true and you are forced to play sports or exercise as a kid?

Furthermore, it doesn't appear to be coincidental in the slightest that these so-called “sex differences” are less and less the younger someone is. They only become pronounced as the years go on.

These social biases cannot possibly be eliminated from scientific studies, as no one can live outside these influences, which is why it is essential to consider them when pondering over these queries.

“Why?” you may be asking still. “And why does any of this matter?”

Because this is yet another example of a societal tool being used to degrade the female identity. Specifically, we see science being used under its “objectivity” veil in order to justify the status quo – the belief that women are weak and less than men.

It can have real, terrible effects upon the lives of individuals who are attempting to thrive through the female identity.

For example, Jazz Jennings, an outspoken, immensely talented trans girl, was not allowed to play on the girls' soccer team at her school, due to the fact that she is “technically a biological male” and thus “might have an advantage over her teammates.” Despite having attended practices, having been trained alongside girls and having been raised as a girl (because she is one), she was denied participation in games solely because of her assigned gender at birth. She's not a star athlete, she's not the strongest on the team, she just wants to be a part of what she rightfully deserves to be a part of, so why is this happening? Assuredly, there is some transphobia involved, but it is undeniable that the ingrained belief that biological females are physically lesser than males is behind this action (hence the claim that “it would be unfair to her teammates”) – an action that is nothing but another example of internalized sexist ideology.

This isn't the only case, of course. Countless women accept this and other such statements and circumstances merely because the societal tools we all praise, like science, tell them it is the undeniable, indisputable truth, and if anyone dares question it, they are considered a no-good, truth-denying radical.

Now, I want you to tell me -- is it radical, or reasonable, to question the nature of clearly biased statements? And should we not, therefore, put all our efforts into realizing the prejudiced nature of what is otherwise considered fact? Should we not question that which justifies the way in which we diminish the value of women in our society? Or should we be happy accepting “the way things are” – in other words, should we settle for being bystanders?

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Using the height percentile calculator

With the help of our height percentile calculator you can calculate what percentile of the population your height falls in, what percentage of people of a given gender, age, and country are shorter or taller than you. It is perfect for answering the questions "What percentile is my height?" and "What percentile height am I?", but the tool can also be used for others, e.g. infants, toddlers and children, including newborn babies. It can serve as a height for age calculator, but note that the results do not constitute health advice. Always consult a certified physician before taking any action related to your health or the health of your child.

To use the height percentile calculator first select a biological sex (gender), then enter the current age of the person: type in whole years manually and select the number of months by rounding to the nearest whole month. For a newborn, enter zeroes in both years and months. The age accuracy is not important if above 20 (adult). Then enter the person's height in feet and inches or in cm or meters. If doing this for your child or toddler, enter their sex (boy or girl), age, and height.

Finally, select the country with whose population you want to compare the height against, or just select "The World" for a worldwide comparison. If choosing a particular country - for adult men and women this should be the country they have spent most of their child and teenage years in order to get a fair comparison. To see the result, press "Calculate Height Percentile" and see which percentile the person falls in. E.g. if they are in the 80th percentile this means they are taller than 80 out of 100 males or out of 100 females, respectively.


American Height Distributions for Women and Men

Unlike weight distributions, height distributions are tame. height is the classic example for a normal distribution. We'll soon have a height by age calculator too, but the surprising thing (versus, say, BMI or weight) is how little the breakpoints change for so many ages.

Most people of approximately normal physical health reach their adult height in their late teens or early twenties, and maintain their daily standing height for around a decade.

Usually in their mid to late thirties, people will start to stand slightly shorter. The causes are legion, but sarcopenia, osteoporosis, and spinal compression are the main causes for most height declines. Other conditions such as scoliosis can also affect standing height.


Different tissues and parts of the body

The majority of skeletal and muscular dimensions follow approximately the growth curve described for height, and so also do the dimensions of the internal organs such as the liver, the spleen, and the kidneys. But some exceptions exist, most notably the brain and skull, the reproductive organs, the lymphoid tissue of the tonsils, adenoids, and intestines, and the subcutaneous fat.

The size attained by various tissues can be given as a percentage of the birth-to-maturity increment. Height follows the “general” curve. The reproductive organs, internal and external, have a slow prepubescent growth, followed by a large adolescent spurt they are less sensitive than the skeleton to one set of hormones and more sensitive to another.

The brain, together with the skull covering it and the eyes and ears, develops earlier than any other part of the body and thus has a characteristic postnatal curve. At birth it is already 25 percent of its adult weight, at age five about 90 percent, and at age 10 about 95 percent. Thus if the brain has any adolescent spurt at all, it is a small one. A small but definite spurt occurs in head length and breadth, but all or most of this is due to thickening of the skull bones and the scalp, together with development of the air sinuses.

The dimensions of the face follow a path somewhat closer to the general curve. There is a considerable adolescent spurt, especially in the lower jaw, or mandible, resulting in the jaw’s becoming longer and more projecting, the profile straighter, and the chin more pointed. As always in growth, there are considerable individual differences, to the point that a few children have no detectable spurt at all in some face measurements.

The eye probably has a slight adolescent spurt, which is probably responsible for the increase in frequency of short-sightedness in children that occurs at the time of puberty. Though the degree of myopia increases continuously from at least age six to maturity, a particularly rapid rate of change occurs at about 11 to 12 in girls and 13 to 14 in boys, and this would be expected if there was a rather greater spurt in the axial dimension (the dimension from front to back) of the eye than in its vertical dimension.

The lymphoid tissue has quite a different growth curve from the rest. It reaches its maximum amount before adolescence and then, probably under the direct influence of sex hormones, declines to its adult value.

The subcutaneous fat layer also has a curve of its own, of a slightly complicated sort. Its thickness can be measured either by X rays or, more simply, at certain sites in the body, by picking up a fold of skin and fat between the thumb and forefinger and measuring its thickness with a special, constant-pressure caliper. Subcutaneous fat begins to be laid down in the fetus at about 34 weeks postmenstrual age, increases from then until birth and from birth onward until about nine months. (This is in the average child the peak may be reached as early as six months or as late as 12 or 15.) After nine months, when the velocity of fat gain is zero, the fat usually decreases (that is, it has a negative velocity) until age six to eight, when it begins to increase once more. Girls have a little more fat than boys at birth, and the difference becomes more marked during the period of loss, since girls lose less than boys. Graphs of the amounts of subcutaneous fat on males and females from birth to 16 years revealed that from eight years on, the curves for girls and boys diverge more radically, as do the curves for limb and body fat. At adolescence the limb fat in boys decreases, while the body fat shows a temporary slowing down of gain but no actual loss. In girls there is a slight halting of the limb-fat gain at adolescence, but no loss the trunk fat shows only a steady rise until adolescence.


Are males taller than females in humans? - Biology

In four years, the average teenage boy will grow a foot taller, put on a stone of muscle, drop an octave in the pitch of his voice and develop 40% more heart muscle.

Boys start growing later than girls, but they are not entering puberty later. Rather, their growth spurt comes at the end of puberty, not the beginning. This delay gives boys the advantage of an extra two years of normal childhood growth before their final growth spurt. This is one of the reasons why adult men are on average 13cm taller than women.

Another reason for their height is that boys grow faster than girls at their peak rate. They grow faster because they have higher levels of testosterone in their bloodstream than girls. The testicles release more and more testosterone into the blood stream as they mature. During puberty an average boy's production of testosterone will increase tenfold.

Testosterone triggers cells all over the body to grow. The skeleton grows in much the same way as in girls, with the arms and legs growing ahead of the torso. But the bones become much denser and heavier than in girls. The final phase of skeletal growth in boys is a broadening of the chest and shoulders. This generally finishes around the age of 20.

Boys' muscles go through a phase of rapid development which girls miss out on. Our muscles are made up of fibres. At puberty in boys, these fibres don't increase in number, but the length and width of existing muscle fibres increases.

Testosterone increases the amount of haemoglobin carried in red blood cells. Haemoglobin is the oxygen-carrying red pigment in red blood cells. Higher levels of haemoglobin enable red blood cells to deliver more oxygen to muscles. This oxygen is used to create energy for muscles to exercise. As a result, teenage boys become fitter and stronger than they have ever been before.

When testosterone levels start to surge inside a boy's body, other things also begin to grow. Find out more about erections.


Sex and Gender

Are you male or female? The answer to this seemingly simple question can have a major impact on your health. While both sexes are similar in many ways, researchers have found that sex and social factors can make a difference when it comes to your risk for disease, how well you respond to medications, and how often you seek medical care. That’s why scientists are taking a closer look at the links between sex, gender, and health.

Many people use the words sex and gender interchangeably, but they’re distinct concepts to scientists.

Defining Differences — Sex is biological. It’s based on your genetic makeup. Males have one X and one Y chromosome Structure made of genetic material and proteins. Humans normally have 46 chromosomes (23 pairs) in each cell. in every cell of the body. Females have two X chromosomes in every cell. These cells make up all your tissues and organs, including your skin, heart, stomach, muscles, and brain.

Gender is a social or cultural concept. It refers to the roles, behaviors, and identities that society assigns to girls and boys, women and men, and gender-diverse people. Gender is determined by how we see ourselves and each other, and how we act and interact with others. There’s a lot of diversity in how individuals and groups understand, experience, and express gender. Because gender influences our behaviors and relationships, it can also affect health.

Influences on Health — “Sex and gender play a role in how health and disease affect individuals. There was a time when we studied men and applied those findings to women, but we’ve learned that there are distinct biological differences between women and men,” explains Dr. Janine Austin Clayton, who heads research on women’s health at NIH. “Women and men have different hormones, different organs, and different cultural influences—all of which can lead to differences in health.”

As scientists learn more about the biology of males and females, they’re uncovering the influences of both sex and gender in many areas of health.

For instance, women and men can have different symptoms during a heart attack. For both men and women, the most common heart attack symptom is chest pain or discomfort. But women are more likely than men to have shortness of breath, nausea and vomiting, fatigue, and pain in the back, shoulders, and jaw. Knowing about such differences can lead to better diagnoses and outcomes.

Men and women also tend to have different responses to pain. NIH-funded researchers recently learned that different cells in male and female mice drive pain processing.

“Without studying both sexes, we wouldn’t know if we’re taking steps in the right direction toward appropriate clinical treatment for men and women,” Clayton says. “Our differences also affect how we respond to medications, as well as which diseases and conditions we may be prone to and how those diseases progress in our bodies.” For example, women metabolize nicotine faster than men, so nicotine replacement therapies can be less effective in women.

Attention to Addiction — Scientists are finding that addiction to nicotine and other drugs is influenced by sex as well. “When it comes to addiction, differences in sex and gender can be found across the board,” says Dr. Sherry McKee, lead researcher at an NIH-funded center at Yale University that studies treatments for tobacco dependence. “There are different reasons men and women pick up a drug and keep using a drug, and in how they respond to treatment and experience relapse. Sex also influences disease risk in addiction. For example, women who smoke are more susceptible to lung and heart disease than men who smoke.”

One NIH-funded research team has detected some of these differences in the brain. In a recent study, 16 people who smoke—8 men and 8 women—underwent brain scans while smoking to create “movies” of how smoking affects dopamine, the chemical messenger that triggers feelings of pleasure in the brain.

These brain movies showed that smoking alters dopamine in the brain at different rates and in different locations in males and females. Dopamine release in nicotine-dependent men occurred quickly in a brain area that reinforces the effect of nicotine and other drugs. Women also had a rapid response, but in a different brain region—the part associated with habit formation. “We were able to pinpoint a different brain response between male and female smokers, a finding that could be useful in developing sex-specific treatments to help smokers quit,” says lead study researcher Dr. Kelly Cosgrove, a brain-imaging expert at Yale University.

Finding better ways to help men and women quit smoking is important for everyone’s health. More than 16 million Americans have diseases caused by smoking. It’s the leading cause of preventable death in the U.S.

Autoimmune Disorders Conditions in which the body’s immune system mistakenly attacks and destroys the body’s own cells. — Scientists have found sex influences in autoimmune disorders as well. About 80% of those affected are women. But autoimmune conditions in men are often more severe. For instance, more women than men get multiple sclerosis (MS), a disease in which the body’s immune system The body’s defense against germs and foreign substances. attacks the brain and spinal cord. But men seem more likely to get a progressive form of MS that gradually worsens and is more challenging to treat.

“Not only are women more susceptible to MS, but women also have many more considerations in the management of the disease, especially since it often begins during child-bearing years,” says Dr. Ellen Mowry, a specialist who studies MS at Johns Hopkins University.

“There are a lot of unanswered questions when it comes to the study of sex differences in MS and other autoimmune disorders,” Mowry explains. “Researchers can learn a lot by studying women and men separately and together, considering possible risk or predictive factors that may differ based on sex or gender, and working collaboratively with other scientists to improve the likelihood of detecting these factors.”

Building Our Understanding — “NIH now requires scientists to ask: ‘What are my research results for males and for females?’” Clayton says. “We need to learn more about the roles of sex and gender in health and disease. Understanding these influences improves health and saves the lives of both men and women.”

You can improve your health and that of your loved ones by being more aware of sex and gender differences. See the Wise Choices box for details, and talk to your health care provider about any concerns you might have.


Here's why men are much more likely to be colorblind

Colorblindness is a fairly common condition where a person's eyes conflate certain colors or don't see colors at all.

It's also way more common in men than in women. But why?

The most commons forms of colorblindness are genetic conditions, passed along the x-chromosome. People with an x-chromosome and a y-chromosome only need their one x to be defective to catch it. People with two x-chromosomes need both to be defective.

Most women have two x-chromosomes (XX), and most men have an x-chromosome and a y-chromosome (XY). That's why colorblindness is much more common in men than in women.

My mother's father was colorblind. He was XY had one defective x-chromosome, which he passed to my mother. But my mother is XX. Her x, which she got from her mother, works fine. So she isn't colorblind. But she is a carrier.

That means that when she has a child, she has a 50% chance of passing that defective x-chromosome along.

My father (XY) passed me a y-chromosome. And my mother passed me her defective x. That means my only x is defective, so I'm colorblind. If they had an XX child tomorrow, that child would have a 50% chance of becoming a carrier like my mother. If my father were colorblind as well (he isn't), that two-x-chromosome child would have a 50% chance of being born colorblind, and would definitely be a carrier.

All of which is to say: It's much easier for an XY person to be colorblind, and most XY people are male. That's why men are much more likely to be colorblind.


Women now account for roughly half of all participants in NIH-supported clinical research, which is subject to NIH's Policy on the Inclusion of Women in Clinical Research. However, more often than not, basic and preclinical biomedical research has focused on male animals and cells. An over-reliance on male animals and cells may obscure understanding of key sex influences on health processes and outcomes.

Accounting for sex as a biological variable begins with the development of research questions and study design. It also includes data collection and analysis of results, as well as reporting of findings. Consideration of sex may be critical to the interpretation, validation, and generalizability of research findings. Adequate consideration of both sexes in experiments and disaggregation of data by sex allows for sex-based comparisons and may inform clinical interventions. Appropriate analysis and transparent reporting of data by sex may therefore enhance the rigor and applicability of preclinical biomedical research.

NIH expects that sex as a biological variable will be factored into research designs, analyses, and reporting in vertebrate animal and human studies. Strong justification from the scientific literature, preliminary data, or other relevant considerations must be provided for applications proposing to study only one sex. Investigators are strongly encouraged to discuss these issues with NIH program staff prior to submission of applications. In June 2020, the Journal of Women’s Health published “Sex as a Biological Variable: A 5-Year Progress Report and Call to Action,” an article commenting on the development and implementation of NIH’s SABV policy, which went into effect in January 2016. Further information regarding NIH expectations for the consideration of sex as a biological variable is provided in this guidance document.


Endurance

Endurance is largely determined by a body's efficiency when converting calories into energy. Female athletes are more efficient than male athletes at converting glycogen to energy. Glycogen is a secondary source of fuel you use when glucose levels drop. This is why female athletes excel in ultra-long-distance sports and rarely hit the wall during long races. It also explains why ultra-running, which includes races longer than a marathon, is one of the few sports where elite female and male athletes regularly compete together, and in which female athletes sometimes win.


Watch the video: Taller or Shorter w. Kate Walsh u0026 Stephen Merchant (January 2022).