Study Uncovers Insights on Why Men’s Growth Rate Has Outpaced Women’s Since 1905

On a global scale, humans have never been greater. The human population has seen its size increase by several centimeters over the last century following industrialization and advances in medicine.

Malnutrition and infectious diseases still hamper human growth in the poorest countries. However, living conditions have generally improved.

Men have grown faster than women in a century

A new study published in the scientific journal Biology Letters recognizes that this improvement in living conditions over the last century has allowed the human body to evolve. However, this development is unequal in the two sexes.

Men and women have grown, but not at the same rate. Since 1905, men have grown (and gained weight) twice as fast as women.

“ To put things into perspective, about one in four women born in 1905 were taller than the average man born in 1905 said Lewis Hasley, professor of environmental physiology at the University of Roehampton and one of the study's authors.

Population growth is linked to the increase in the human development index

Nevertheless, ” this figure fell to around one in eight women for those born in 1958 », he adds. To reach this conclusion, researchers from Italy, the United States and the United Kingdom analyzed data provided in 2003 by the World Health Organization. They included the height and weight of more than 100,000 people in 69 countries.

The researchers also took into account the Human Development Index (HDI), which aims to assess the quality of life of a country's nationals.

“ People living in low HDI countries are more likely to suffer from infectious diseases, chronic poor diet, and a greater overall disease burden than people living in high HDI countries “, explains Lewis Hasley.

Childbirth and pregnancy are said to hinder women's growth

Human growth is therefore more limited in these countries. As for other countries, researchers are trying to understand why the difference between women and men has widened. In particular, they suggest that women are “ more ecologically constrained “.

In other words, they would be limited by the demands of pregnancy and childbirth. In countries with a high HDI, men have access to more energy-rich foods. This would allow them to further develop their bodies, according to the researchers.

Another factor that could explain this growth of men over women is sexual selection. In 2014, a study already looked at the relationship between men's romantic success and their height.

The man being taller than the woman in a relationship is a universal preference

“ There seems to be almost universal agreement between men and women that they would prefer to be in a relationship where the man is taller “, says Abigail Weitzman, author of this study.

So if women choose more tall men, their genes are passed on to subsequent generations, gradually increasing the size of the population over time.

The new study also offers a more subtle theory. What if men's height was seen as a guarantee of having healthy children?

Attraction would not be the only reason behind men's choice of size

“ Women may find men's height attractive because, potentially, it makes them look more formidable, but also because being taller suggests that they are shapely », adds Lewis Hasley.

Aesthetics would therefore not be the only reason behind this attraction towards taller men. Either way, it helps make the population larger over the decades.

The researchers acknowledge that more in-depth studies should be conducted. We need to better understand why the life index is directly linked to the height and weight of the human being.

Source: IFLScience