Why are men taller than women, on average?
On average, human men tend to be around 5 inches (13 centimeters) larger than women. But why?
In short, we are not sure. Even if this difference in height linked to sex exists around the world, we always lack a complete scientific understanding of reason. But we have some signs of genes and hormones linked to sex which help to unravel this mystery.
Height is a complex line influenced by many factors. One of them is genetic: Genes on sex and regularly chromosomes help determine the height. Each baby receives two sets of chromosomes: 23 from their mother and 23 from their father. Two of these chromosomes are sex chromosomes: women tend to be XX and males are generally xy. Parents often contribute genes consistent with their own characteristics, so generally older parents will have larger children than shorter parents.
Identical twins studies have found that the height is roughly 80% hereditaryThis means that around 80% of height differences can be attributed to genetics.
But unraveling the genes that contribute to the height are complicated. “Height is a famous polygenic line,” Alexander BerryA scientist in bioinformatics of Geisinger College of Health Sciences in Pennsylvania, told Live Science. This means that many genes influence it. The height can vary madly depending on the thousands of genes affecting throughout the genome. “Association studies on the scale of the genome that look at the size find blows throughout the genome,” said Berry.
A 2022 article published in the journal Nature found 12,1111 places in the genome where only one nucleotide – the G, A, T or C in a DNA Sequence – varies and is significantly associated with height.
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One of the best -studied genes linked to the height is called Shox, which is both on chromosomes X and Y. It is estimated that Shox represents about 25% of the average disparity of 5 inches between men and women, said Berry. He added that the variants of genes in which Shox loses its function on the X or the chromosome can cause a considerably reduced height. For example, genetic disorder Léri-weill dyschondrostosiswhich is caused by a transferred shox gene, affects bone growth and leads to a short stature.
Another place to study height disparities is in people with an aneuploidy sex chromosome, or an atypical number of chromosomes, such as xxx or xxy. In an article published in May 2025 in the journal PNABerry and his team studied 928,605 people using data from three biobanks. From this group, 1,225 people had chromosomal sexual aneuploidism. In these people, researchers have studied how the dosage – or the number – genes affects these sex chromosomes. In other words, how more or less specific genes on these missing x and y affected the height?
The results highlighted the way Shox affects the height in the male and medium -sized women. The team noted that more chromosomes had an impact on height more than more chromosomes X. In general, those who have additional YS tend to be larger than those who have additional Xs. This is partly because those with XX chromosomes have a inactive xThis means that it does not all transcribe the same genes, including the Shox. But someone with XY chromosomes has two sets of transcribed shoxes. For the male and medium women, this observation maintains that the expression of Shox occurs at a higher rate in those with xy chromosomes than in those with XX.
But Berry warned that this observation does not mean that the chromosome itself is responsible for this disparity.
“Our data does not show it at all,” he said. The Shox occurs on X and Y chromosomes, so its impact on height is not unique to men. However, Berry said there may be codings specific to the Y chromosome which have an impact on hormones, as testosteronewhich, in turn, can influence vertical growth. Testosterone is a hormone produced by male and female sexual organs, although males make it naturally more. Androgen, testosterone is responsible for the development of generally male characteristics as a deeper voice and No more body hair.
“It is likely that other genes on the chromosome influence hormone production, directly or indirectly,” he added. However, “the relationship between hormones and the height is complicated”.
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Other hormones also contribute to growth. Human growth hormone comes from the pituitary gland, promoting the growth of children. Insulin 1 growth factor 1 (IGF-1) intervenes on the effects of human growth hormone, both culminating in puberty.
But in the history of hormones and size, “the estrogen is a star”, ” Holly DunsworthA professor of anthropology at the University of Rhode Island, told Live Science. Produced in men and women during puberty, estrogens “is a major engine of long bone growth,” she said.
Regarding bone growth, estrogens work in two phases. The first phase implies the driving height. During the second phase, there are ultimately so many estrogens that the bones oses or merge, said Dunsworth. Once the production of estrogens culminates in adolescents, their bones are dared. Estrogens’ production culminates earlier in women compared to men, who continue to grow.
Dunsworth is the author of an article in 2020 published in the journal Evolutionary anthropology Exploration of the role of estrogen in the difference in height between men and women. Above all, this hypothesis affirms that estrogens can partially explain the Gulf of growth, as opposed to evolutionary speculation according to which men, as a supposedly more aggressive sex, have simply evolved to be greater.
That said, a person’s sex is not the only factor that influences size; Of course, some women are higher than men.
Beyond genetics and hormones, the environment also plays an important role. Since the height is 80% hereditary, 20% are allocated to environmental factors, such as nutrition and climate. This confluence of drivers has made it difficult for researchers to definitively respond to the reason why men tend to be larger than women. But Berry thinks that another factor – the expression of genes – could be the next key to this mystery.
“I think we could see, with more important gene studies, this variation of height even between people with the same chromosomes varies due to the expression of genes.”
