It has recently been announced that the International Olympic Committee (IOC) has issued new guidelines that transgender athletes should be allowed to compete in the Olympics and other international sporting events in their reassigned “gender” without undergoing sex reassignment surgery.

The main physical restriction the new guidelines place on males who transgender will be that their testosterone level must be below a certain level for one year prior to the event they are competing in.

This means that transwomen who retain their male sex organs (testes and penis) but who have some hormone treatment to reduce their testosterone level for a year will be able to compete with women (by which I mean biological females who were raised as girls).

Unsurprisingly many women are extremely disturbed by this development, not least because the physical differences between the sexes go far beyond testosterone levels. After puberty few of these differences are eradicated simply through treatment to reduce a transwoman’s testosterone levels. I provide a summary of key differences below.

The main reason for sex-segregated sports is to create a level playing field. Sport is widely recognised to have many benefits throughout life, but particularly during childhood and adolescence. It is good for physical and mental health; it generates confidence and physical strength; it teaches girls and young women to defend their boundaries; it encourages team spirit and cooperation; and it provides an opportunity for bonding. Taking part in sports can make a significant impact on a girl or young woman’s life chances.

Sex-segregated sports provide an opportunity for female bonding. Typically males have many more opportunities for male-only bonding than females. For more on the need for women-only spaces, see What is a Woman?

Girls and young women are under huge pressure about their body image and live in a hyper-sexualised misogynistic culture that is saturated with the male gaze. Sports have traditionally provided girls and young women with an important respite from this. There is very real risk that the presence of transwomen who have been raised male and may have full male genitalia will have an impact on this respite and the freedom that a female-only sporting environment gives girls and young women.

Here is a photo of a 50-year old post-op transwoman called Gabrielle Ludwig who was able to join a girls’ college basketball team.

Ludwig’s height, while tall, is not that unusual for a man. But it is extremely rare for a woman to be that tall. Obviously basketball is a sport where height is a key advantage. How is Ludwig’s inclusion in a girls’ team fair – given that one of the key purposes of sex-segregated sports is to enable people to compete on a level playing field with their peers?

With the new IOC guidelines that no longer require transwomen to undergo SRS surgery to participate in female sports, we are likely to see a lot more similar cases.

Imagine being a young female track athlete being forced to compete against transwomen who are biologically male, with all the advantages that brings to speed and strength – while everyone pretends that it is a level playing field. How would that feel? And how would it feel if, because of their biological advantages, the women athletes got replaced by transwomen?

Tell me how is that fair? What about girls and women’s rights to participate in sports on a level playing field?

How is taking away the rights of women and girls and giving new rights to transgendered people fair?

The IOC guidelines have a much greater potential negative impact on women and girls than men and boys. I therefore believe that they contradict the rights of women and girls to equality as enshrined in the Universal Declaration of Human Rights* and violate Article 30 which states:

“Nothing in this Declaration may be interpreted as implying for any State, group or person any right to engage in any activity or to perform any act aimed at the destruction of any of the rights and freedoms set forth herein.”

I believe that there are other, fairer, ways to solve the rights of transgendered people to participate and compete in sports and I call upon the IOC to reconsider its guidelines.

* The Universal Declaration of Human Rights was proclaimed in 1948, when the definitions of man and woman were based on firmly sex and not the more fluid and ill-defined concept of gender.

Physical differences between the sexes

I provide below a simple summary of key biological differences between the sexes. These are in addition to the obvious differences in chromosomes, hormone levels, primary and secondary sex characteristics and reproductive capacity.

This summary is based on an assignment by Sarah Lund for a sports therapy course. Her reference was Hands on Sports Therapy by Keith Ward.

Anatomical differences

Adult Females Adult Males Shorter Taller by approximately 10% on average Lighter Heavier by approximately 15% Bones are lighter and thinner Bones are heavier and thicker Surface of joints smaller Surface of joints larger Muscle attachment sites less distinct Muscle attachment sites more distinct Shoulders narrow Shoulders broad Smaller thorax Larger thorax Breasts No breasts Broader hips Narrower hips Pelvis shallower with larger, oval-shaped pelvic brim Pelvis deeper with smaller, heart-shaped pelvic brim Proportionately shorter legs with neck of femur at a greater angle to its shaft Proportionately longer legs with neck of femur at a lesser angle to its shaft Greater slant of the thigh to the knee Lesser slant of the thigh to the knee More likely to demonstrate Genu Valgus (Knock-Knee) posture, therefore anatomically disadvantaged in running activities and prone to a variety of overuse injuries Less likely to demonstrate Genu Valgus (Knock-Knee) posture Arms proportionately shorter with more of a carrying angle (the angle of forearm in relation to upper arm) – an anatomical disadvantage in lifting and throwing activities. Arms proportionately longer with less of a carrying– an anatomical advantage in lifting and throwing activities. Wider hips also an anatomical disadvantage in lifting and throwing activities. Narrower hips also an anatomical advantage in lifting and throwing activities.

Body composition

Adult Females Adult Males Endomorphic tendency Mesomorphic tendency Greater percentage of body fat – around 25% on average Lesser percentage of body fat – around 13% on average Lower lean body mass (fat-free mass) indicating reduced muscle mass Higher lean body mass (fat-free mass) indicating increased muscle mass Tend to deposit more fat on hips and thighs Tend to deposit more fat around waist and upper body Lesser percentage of blood in body fluid and less water Greater percentage of blood in body fluid and more water

Cardio-vascular differences

Adult Females Adult Males Smaller heart Larger heart Lesser stroke volume (the amount of blood pumped out of the heart during each contraction.) Greater stroke volume Higher resting heart rate Lower resting heart rate Blood pressure lower Blood pressure higher Carry less erythrocytes and lower levels of haemoglobin in blood cells Carry more erythrocytes and higher levels of haemoglobin in blood cells

Respiratory differences

Male lungs, being larger, have an increased respiratory rate and a greater vital capacity.

Performance differences

All of these differences add up to significant performance advantages for men in most sports. After puberty, few of these things will change significantly even with hormone treatment.