Why are men taller than women? Genes hold the answer – Firstpost

Men are generally taller than women. The two sexes have an average height difference of about five inches.  

While this is a known fact, a question worth asking is: Why are men taller than women? Scientists have found an answer, which partially explains this: genes.  

But how? Let’s understand.  

How the study was conducted  

A new study published in the journal Proceedings of the National Academy of Sciences on Monday (May 19) involved the genetic data of nearly one million (10 lakh) people.  

Researchers studied data from three biobanks – two in the United States and one in the United Kingdom.  

Of the roughly one million people whose information was in the biobanks, the scientists found 1,225 people had missing or extra X or Y chromosomes, as per a New York Times (NYT) report.  

While men have one X and one Y chromosome, women have two X chromosomes.  

The gene behind height difference

Scientists have found that a gene called SHOX is responsible for the difference in male and female heights.  

Also called short stature homeobox-containing gene, it is linked to height. SHOX is present on both the X chromosome and the Y chromosome.  

After studying the genetic data of more than 1,000 people who had either missing or extra X or Y chromosomes, researchers discovered that an additional Y chromosome gave a greater height boost than an extra X.  

Matthew Oetjens, a genetics researcher at Geisinger College of Health Sciences in Danville, Pennsylvania, explained that the SHOX gene is placed near the end of the sex chromosomes, as per NYT.  

In women, most genes on one of the two X chromosomes are inactive. However, the genes are active at the very tip of the X. The SHOX gene’s closeness to the tip ensures that it remains active.  

In males, both X and Y chromosomes are fully active and so is the SHOX gene.  

This means that the SHOX gene will provide more height to men than women. Researchers say this gene makes up for roughly a quarter of the average height difference between men and women.  

Eric Schadt, a professor in the department of genetics and genomic science at Mount Sinai School of Medicine in New York City, told NYT that the study was “definitely cool”.  

“It is a great use of these biobanks to uncover what is still somewhat of a mystery,” he said. “Even though the effect is modest, it does explain 20 per cent or so of the height difference.”

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Other recent studies on human height

Another study, published in January, found that men have grown and increased in weight twice as fast as women over the past century, further raising the differences between the two sexes.  

Researchers also previously found that women are more interested in taller men than men are in shorter women. However, being taller is not always a good thing.  

Taller people are at greater risk of developing certain types of cancer. This could be because these people have more cells that can accumulate mutations, leading to the potentially fatal disease.  

With inputs from agencies