Boys are stronger and faster in almost all stages of life

Studies have consistently proven that there are significant strength, speed and stamina differences between males and females of all ages. 

It is the very reason we have separate sporting categories in the first place. 

In many areas of life sex differences simply do not matter, but in sport, change rooms and sex specific services it really does matter. 

Women and girls deserve sex-based protections and provisions in these areas.

In sport, separate divisions are essential, unless the female athlete consents to playing in a mixed sex competition. 

Feelings don’t determine or change the physical reality of bodies.

One researcher, Greg Brown, has documented male and female differences in prepubescent children in athletics. 

Brown examined finishing scores from boys and girls who competed in the U.S. Track and Field National Youth Outdoor Championships and the National Junior Olympic Championships. Brown found that boys in the 8 and under and 9-10-year-old age groups outperformed the girls in many events. Moreover, the magnitude of the sex difference was event-specific. For the 100-m and 200-m sprints, which rely primarily on lower-limb strength and power, the boys outperformed the girls by 3–6%. However, for the shot put and javelin throw, which rely more heavily on upper-limb strength and power, the boys outperformed the girls by 7–33%. 

Results from our two recent meta-analyses on childhood sex differences in muscle strength support Brown’s findings. 

James Nuzzo, an exercise physiologist who I met in Western Australia, has recently undertaken and published studies regarding grip strength differences. 

In our first study, we examined sex differences in grip strength from birth to age 16. We gathered every study that we could find that compared boys’ and girls’ grip strength. We found 169 studies. They were conducted in 45 countries between 1961 and 2023 and included over 175,000 boys and over 175,000 girls.

We found that boys were stronger than girls at all ages, though the results in children younger than three years old should be interpreted with caution due to the limited and heterogenous data available and because the sex difference at 1-2 years old was not statistically significant. Nevertheless, a clear, statistically significant sex difference in grip strength was present at age 3, and that difference remained constant until age 11, with girls having about 90% of boys’ grip strength. At age 11, boys were still stronger than girls, but the difference in grip strength narrowed for that year, presumably because girls reached puberty earlier than boys. Then, from age 12, the difference in grip strength started to widen considerably. By age 16, girls had about 65% of boys’ grip strength. 

Regardless of time or place, the researchers concluded that male and female biology significant impacts strength results.

In our second study, we examined childhood and adolescent sex differences in all strength tests other than grip strength. We compartmentalized these tests into upper-limb strength tests and lower-limb strength tests. We did this because sex differences in strength in adults are muscle-specific. For example, in lower-limb muscles, women have 60-70% of adult male strength. In upper-limb muscles, women have only 50-60% of adult male strength. 

We aggregated data from 34 studies. The studies were conducted in 10 countries and across several decades and included a total of 3,497 boys and 3,137 girls who were 5-17 years old.

Again, we found statistically significant sex differences in muscle strength at all ages. Similar to adults, the size of the sex difference in strength was greater in the upper limbs than the lower limbs. In 5-10-year-olds, the sex difference in lower-limb strength was 8%, whereas it was 17% in upper-limb strength. In 14-17-year-olds, the sex difference in lower-limb strength was 30%, whereas it was 50% in upper-limb strength. These limb-specific sex differences in strength are also consistent with Greg Brown’s studies which showed that the greatest sex differences in athletic performance are observed in events that rely heavily on upper-limb strength.