Sport and Transgender Youth
Sport is one of the few domains where the biological reality of two sexes becomes directly and measurably visible. This applies to elite sport, but — contrary to what is often suggested — also to youth sports. A sports policy that ignores the performance differences between biological boys and girls in the name of inclusion ultimately shortchanges the girls and young women for whom girls’ and women’s categories were originally created.
The body develops in sex-specific ways — even before puberty
It is often claimed that physical differences between boys and girls only emerge at puberty. That is partly true, but not entirely. Even before puberty, measurable differences exist in muscle mass, cardiorespiratory capacity, haemoglobin and gross motor development, partly as a result of pre- and postnatal androgen exposure. During and after puberty, these differences increase significantly: longer limbs, larger hearts and lungs, greater muscle mass, higher bone density and higher haemoglobin levels. Much of this is retained, even after later hormone therapy.
What puberty blockers do — and do not do — in this context
For a biologically male young person who receives puberty blockers before male puberty, the typically male advantages partly fail to develop. That may sound like a solution to the issue of fairness in sport — but it amounts to trading a social fairness problem for a medical one: lower bone density, impaired growth, consequences for sexual development and an almost certain progression to lifelong hormone therapy. A solution that permanently damages a child’s physical development is no solution. See Puberty Blockers and the Dutch Protocol.
For a biological boy who has gone through male puberty and subsequently receives oestrogen, a substantial proportion of the physical advantages remain. Research (including Hilton & Lundberg, 2021) shows that 12 months of hormone therapy does not eliminate the performance advantages.
The interests of girls and young women matter too
Girls’ competitions exist because otherwise girls would have little chance of achieving results against boys of the same age. Allowing biological boys into these competitions without qualification — whether in football, rugby, cycling, competitive swimming or combat sports — undermines the very reason these categories exist. This is not an abstract philosophical issue: it concerns podium places, scholarships, the risk of injury in contact sports and the fairness of the entire sporting system for girls.
Safety in contact sports
In contact sports (rugby, football, combat sports, hockey), there is an additional dimension: the risk of injury. In 2020, World Rugby concluded on the basis of safety research that transgender women should not compete in women’s elite competitions. There is also growing recognition in youth competitions that protecting girls from injury is a legitimate interest that may outweigh a claim of inclusivity.
Recreation versus competition
In purely recreational sport, the interests are different from those in competitive sport. A child taking part in a gymnastics club or a neighbourhood tournament benefits from participation and enjoyment — and tailored solutions can be found without fundamentally abolishing the girls’ or boys’ category. In competitive sport, where places, titles and progression to elite sport are at stake, a clear classification based on biological sex is the fairest approach.
Policy in motion
International sports federations are becoming increasingly clear. World Aquatics (swimming), World Athletics (athletics), the UCI (cycling) and World Rugby impose restrictions preventing biological boys who have gone through male puberty from competing in the women’s category. Dutch sports federations are lagging behind on this issue, often under pressure from inclusivity organisations. A renewed debate is under way and is welcome. In the United States, the Supreme Court confirmed that states may exclude trans women from girls’ and women’s sports, and the IOC restored the women’s category in elite sport. The broader debate is covered in the article on gender and sport.