A gender specialist at the University of Genoa, in Italy, a psychologist at the University of Missouri, in the U.S., and a behavioralist at the University of Roehampton, in the U.K, have found that men are growing taller and heavier at twice the rate of women. In their study published in Biology Letters, the researchers analyzed a century’s worth of data in the World Health Organization’s database and found evidence of a growing sexual dimorphism in humans.

Prior research has shown that sexual size dimorphism exists in many species—in many, males are larger, due to competition for mates, or female preferences. In others, females are larger, generally for reproductive reasons. In humans, males are on average taller, more muscular and heavier than females. Prior research has shown the size difference has likely been due to males competing for females, with larger men tending to win such battles in times past.

In the modern age, such battles appear to be less of a factor, though males are still growing large. Some scientists have suggested this is because women prefer to mate with larger men. For this new study, the researchers looked at sexual size dimorphism in humans over the past century.

The researchers accessed the WHO database of information on millions of people going back to 1900. They analyzed data for approximately 135,000 people from 62 countries around the world and found that both men and women have been growing taller and heavier due to improvements in diet and health care. They were also able to compare height and weight ratios between males and females. They found that males have been growing taller and heavier at twice the rate of females.

The researchers note that such a rapid increase in size and weight by males has some drawbacks, mostly due to health issues. Taller men tend to be more prone to developing cancer, for example. They must also eat more to maintain their stature, which can lead to cardiovascular problems.