Weird how the CDC charts you gave me place 7 year olds at almost identical in height and weight categories. I am aware boys are about 1cm taller on average around 12-24 months, but honestly... is this relevant? I doubt anyone is worried about the sanctity of 1 year old sports.

The links I provided show the various charts the CDC and WHO use at various ages of childhood, starting at birth. It's disingenuous to focus on the CDC charts for age 7 only.

If you looked into the matter more, you'd know why it is that age 7 girls & boys are the same height and weight: whilst males grow faster in early childhood, girls grow faster later on.

Also, if you knew more about this, you'd also know that sex differences that develop and exist in utero, infancy and early childhood can and do have profound impacts for what happens at those times in life as well as later on.

We CAN add bone density to the list.

Yes, bone density - and a lot of other factors, too. Such as the muscle mass of the left ventricle of the heart.

In childhood prior to puberty, the mean advantage males have over females in the amount of LV muscle mass is 6%, which is considered small compared to the male advantage in LV muscle mass that exists during and after puberty, which is 25-38%. But in sports the difference between winning, losing and not qualifying for competition at all often comes down to a tenths or hundredths of a second (or in elite sports, thousandths and millionths of a second). So in an athletics context, the fact that the average boy has a 6% advantage in LV muscle mass over the average girl can still be hugely significant.

https://www.ahajournals.org/doi/full/10.1161/01.HYP.26.6.979

And then there's lung capacity, which obviously has a huge impact on athletic ability:

Female lungs tend to be smaller and weigh less than those of males and, on average, may contain fewer respiratory bronchioles at birth. The number of alveoli per unit area and alveolar volume do not differ between boys and girls, but boys have larger lungs than girls. Thus, the total number of alveoli and alveolar surface area are larger for boys than for girls of a given age.

Whereas large airways tend to grow faster than parenchymal tissue in young females, the growth of large airways tends to lag behind that of the parenchyma in young males in a phenomenon known as dysanaptic growth, resulting in relatively narrower airways in young males than in young females. Maturation of the airways and lungs continues through childhood and into adolescence during which time, for the most part, males continue to have larger lungs than females. Further, the conducting airways of adult males are larger than those of adult females, even when lung or body sizes are equivalent.

Minor changes in lung structure and development can have a major impact on respiratory health in later life.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2391086/

At birth, females have smaller lungs than males with fewer respiratory bronchioles [1]. The sex-related differences in lung growth persist from childhood to adulthood. They are present also during the brief period of adolescence (from 11 to 13 years) when females are taller than males, because of the onset of the pubertal growth spurt.

Because boys have bigger lungs per unit of stature, they have a larger total number of alveoli and a larger alveolar surface area for a given age and stature.

The intrinsic elasticity of lung parenchyma is similar between sexes, whereas the recoil pressure differs because of the differences in lung size and in maximum distending forces.

The shape of the lung differs between males and females, being more pyramidal in the former and more prismatic in the latter.

The aforementioned sex-based differences in the structure and function of the respiratory system become critically important during dynamic exercise. The differences between women and men [some of which in the respiratory system are present from birth] impact the development of flow, the regulation of lung volume, the pressure swings and the consequent work of breathing.

And so on.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5980468/

BTW, some of the lung differences between male and female lungs and overall respiratory capacity give baby girls' survival advantages over boys in the case of certain neonatal illnesses. And these and all the other differences between the sexes allow females to do things males can't, such as conceive & gestate human offspring. I'm just focusing on the differences that exist in children prior to puberty that give boys a leg up - or two - in sports since those are specifically the issue here.

Sorry for the link that broke. If you're interested, a search for "president's physical fitness test boys and girls charts" will bring up plenty of results.

As to your question

is this relevant? I doubt anyone is worried about the sanctity of 1 year old sports.

I was responding to your earlier post in which you responded to Sloane's claim that "male bodies are different in ways that matter athletically before puberty" by asserting most emphatically and with an unwarranted air of authority:

They aren't. Not even a little. The BEST I could find is pre-puberty boys have less body fat. BMI, Height, Weight, and Lean Mass are all almost identical until about 10-11 years old (the puberty age).

It's true that one-year-olds aren't competing in sports. But babies and toddlers of both sexes do play and attend daycare/nursery and classes together. And the physical differences between male and female crawlers and toddlers of the same exact chronological age play a large role in what happens between the kids, and in which ones are most likely to pushed over (or down the stairs) and end up hurt.

Moreover, a lot of kids start playing sports pretty early. LL starts official Tee ball leagues at four. And whilst theoretically Tee ball has been open to both sexes since the 1970s, after mixed-sex Tee ball was introduced, LL eventually had to reinstate an an all-male category of Tee ball starting at age four because of the performance differences in the two sexes even at such an early age.

Mini-puberty is nebulous water to tread. Even one of the papers you linked said there are conflicting studies on the impact of testosterone in <36 month boys and growth.

I don't understand what you mean by "nebulous water to tread."

Yes, there are conflicting studies, as there are in many areas. And the mini puberty of infancy is insufficiently researched. But the fact is, starting in utero and throughout the rest of human development prior to puberty, there are TONS of differences between males and females that matter in sports - when initially you claimed that there aren't any.

Puberty starts at 10.

This is not true, although puberty can and often does start at 10 or before.

Puberty starts at 10.

No many how many times you repeat it, such a blanket statement doesn't become any truer than when you said it the first time.

The age at which puberty starts varies considerably between the two sexes, amongst different races, ethnicities and countries of residence. It also varies considerably amongst individuals within sex and race/ethnic and nationality categories. Kids in the same family, even those of the same sex within the same family, often begin puberty at markedly different ages.

USA health officials say puberty

usually happens between ages 10 and 14 for girls and ages 12 and 16 for boys.

https://medlineplus.gov/puberty.html

The UK's NHS says puberty says

The average age for girls to begin puberty is 11, while for boys the average age is 12.

But it's different for everyone, so don't worry if your child reaches puberty before or after their friends.

It's completely normal for puberty to begin at any point from the ages of 8 to 14. The process can take up to 4 years.

https://www.nhs.uk/live-well/sexual-health/stages-of-puberty-what-happens-to-boys-and girls/#:~:text=Puberty%20is%20when%20a%20child's,the%2

What some other sources say:

https://kidshealth.org/en/kids/boys-puberty.html

https://www.healthline.com/health/parenting/stages-of-puberty#tanner-stage-1

https://www.medicinenet.com/puberty/article.htm

There's no shame in not knowing much about infant and child development. But people who know little about the topic really should think twice before making sweeping pronouncements about it as you have done. Especially as you are advocating giving experimental medical treatments to children of both sexes with GD starting at puberty with the attempt to outfox biology and prevent puberty.