On average, human males tend to be about 5 inches (13 cm) taller than females. but why?
In short, we are not sure. This gender-related height difference exists all over the world, but there is no complete scientific understanding of why. However, we have some sex-related genes and hormones that will help us unravel this mystery.
Height is a complex characteristic that is influenced by many factors. One of these is genetics. Both sex-related and regular chromosomal genes help determine height. Every baby receives two sets of chromosomes. 23 sets from mother and 23 from father. Two of these chromosomes are sex chromosomes. Women tend to be XX, while men usually have XY. Because parents often contribute to genes that match their traits, tall parents are usually able to have taller children than shorter parents.
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A study of the same twins found that height was about 80% hereditary, with about 80% of differences in height likely to be due to genetics.
However, it is complicated to understand which genes contribute to height. “Height is a well-known polygenic trait,” Alexander Berry, a bioinformatics scientist at Geisinger University of Health Sciences in Pennsylvania, told Live Science. This means that many genes affect it. Height can vary widely based on thousands of genes affecting the entire genome. “Genome-wide association studies looking at height find hits across the genome,” Berry said.
One of the 2022 papers published in the Nature Journal found 12,111 locations in the genome where G, A, T, or C differed in DNA sequences and a single nucleotide (G, A, T, or C) is significantly associated with height.
Related: What determines a person’s height?
One of the most studied genes connected to height is called SHOX and is located on both the X and Y chromosomes. Shox is estimated to account for about 25% of the 5-inch average disparity between men and women, Berry said. He added that gene mutants in which shox can lose function on the x or y chromosomes can significantly reduce height. For example, the genetic disorder caused by the mutated shox gene, leri-weille dyschondrosteosis affects bone growth and leads to shorter heights.
Another place to investigate height disparities is people with sex chromosome aneuploidy, or those with atypical chromosomes such as XXX or XXY. In a paper published in the Journal PNAS in May 2025, Berry and his team studied 928,605 people using data from three biobanks. Of this group, 1,225 people suffered from sex chromosomal aneuploidy. In these people, researchers have studied how the dose or number of genes affects these sex chromosomes. In other words, how did many of these extra or missing XS and YS specific genes affect height?
The findings shed some light on how Shox affects the height of average men and women. The team discovered that more Y chromosomes affected their height, more than more X chromosomes did. In general, those with extra YS tended to be taller than those with extra XS. This is because patients with the XX chromosome have one inactive X and therefore do not transcribe all the same genes containing SHOX. However, people with the XY chromosome have two sets of transcription SHOX genes. For the average male and female, this finding supports that SHOX expression occurs at a higher rate in patients with XY chromosomes than XX chromosomes.
However, Berry warned that this finding does not mean that the Y chromosome itself is the cause of this disparity.
“Our data doesn’t show that at all,” he said. SHOX occurs on both X and Y chromosomes, so the effect on height is not unique to males. However, Berry said there could be Y chromosome-specific coding that affects hormones like testosterone. Testosterone is a hormone produced by both male and female genitals, but men naturally do it more. Testosterone, an androgen, is responsible for the development of typical male characteristics such as deeper voice and body hair.
“It is likely that other genes on the Y chromosome will directly or indirectly affect hormone production,” he added. However, “the relationship between hormones and height is complicated.”
Related: Why do women tend to outperform men?
Other hormones also contribute to growth. Human growth hormone is born from the pituitary gland and promotes growth in children. Insulin-like growth factor 1 (IGF-1) mediates the effects of human growth hormone, both peaking during puberty.
But in the story of hormones and height, “estrogen is a star,” Holly Dancesworth, anthropology professor at the University of Rhode Island, told Live Science. Estrogens produced in both men and women during puberty are “the major drivers of long bone growth,” she said.
When it comes to bone growth, estrogen works in two stages. The first phase includes height driving. In the second stage, Dunsworth said, ultimately there is a very high estrogen and there is a foliar or fusion of bones. When estrogen production peaks in adolescents, their bones absorb the leaves. Estrogen production peaks faster in women compared to growing men.
Dunsworth wrote a 2020 paper published in the journal Evolutionary Anthropology, which explores the role of estrogen in differences in height between men and women. Importantly, this hypothesis argues that estrogen may partially explain the bay of growth.
That said, it is not the only factor that affects your height. Of course, some women are taller than men.
Beyond genetics and hormones, the environment also plays an important role. Because he is 80% tall, 20% is due to environmental factors such as nutrition and climate. This convection of drivers made it difficult for researchers to clearly answer why men tend to be taller than women. However, Berry believes that another factor, gene expression, could be the next key to this mystery.
“I think in some larger gene expression studies we might find that height variations are altered by gene expression even among people with the same chromosome.”
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