Plain Language Summary
Gender identity is an important issue in society, yet its causative
mechanism is poorly understood. The main anatomical differences between
males and females are the genitalia and the brain. This paper reviewed
the literature to explore the link between genetic influences and brain
development, and their impact on gender identity. Investigating these
developmental mechanisms could lead to advances in the understanding of
gender dysphoria, a condition whereby an individual’s gender and
biological sex are mismatched. Exploring the biochemical development of
the genitalia highlights the differences between males and females,
notably how testosterone elicits the pathways of male development in an
embryo. When research has been conducted in people with Androgen
Insensitivity Syndrome, a condition where the testosterone receptor is
mutated and faulty, and thus cannot function, gender dysphoria is
observed as the body is genetically male but anatomically female.It is known that the structure of male and female brains
differs; it is found that people with gender dysphoria have a brain
structure more comparable to the gender to which they identify. The
review of the literature suggests that there is a disparity between the
brains of those who identify differently to their assigned gender at
birth, highlighting a multifactorial underpinning of the gender
identity. Further research is required to shed light on the molecular
mechanism of this, allowing for greater education and understanding of
this scientific and social phenomenon.
Abstract : There is a durable biological underpinning to
gender identity that should be considered in policy determinations .
Medical intervention for transgender youth and adults (including puberty
suppression, hormone therapy and medically indicated surgery) is
effective, relatively safe (when appropriately monitored), and has been
established as the standard of care. Federal and private insurers should
cover such interventions as prescribed by a physician as well as the
appropriate medical screenings that are recommended for all body tissues
that a person may have. Increased funding for national pediatric
and adult transgender health research programs is needed* to
close the gaps in knowledge regarding transgender medical care and
should be made a priority.
*NOTE: Remember what I said about how studies always or almost always
will say further study is needed. This one is pretty upfront about why.
We need money.
Amir, Hadar / Perl, Liat / Barda, Shimi / Lantsberg, Daniel / Becker,
Anat Segev / Israeli, Galit / Azem, Foad / Oren,
Adolescent
Transgender Females Present Impaired Semen Quality That Is Suitable for
Intracytoplasmic Sperm Injection Even Before Initiating Gender-Affirming
Hormone Treatment 2022 Reproductive Sciences , Vol. 29 p. 260-269
https://doi.org/10.1007/s43032-021-00561-y \cite{Amir2022}Abstract: The present study aimed to determine the semen
quality and cryopreservation outcomes among adolescent transgender
females at the time of fertility preservation (FP) before initiating
gender-affirming hormone (GAH) treatment. This retrospective cohort
study included 26 adolescent transgender females who underwent FP in our
Fertility Institute between 06/2013 and 10/2020. Pre-freezing semen
parameters were compared to WHO 2010 reference values. Post-thaw semen
parameters were used to determine the adequate assisted reproductive
technology (ART). A multivariate linear regression analysis was
performed to assess the impact of medical and lifestyle factors on semen
quality. The mean age at which adolescent transgender females underwent
FP was 16.2 ± 1.38 years. The median values of all semen parameters in
our study group were significantly lower compared to the WHO data,
including volume (1.46 mL vs 3.2 mL, respectively, P = 0.001 ), sperm
concentration (28 × 106/mL vs 64 × 106/mL, P < 0.001), total
sperm number (28.2 × 106 vs 196 × 106, P < 0.001), total
motility (51.6% vs 62%, P < 0.001), and normal morphology
(2% vs 14%, P < 0.001). The frequency of semen abnormalities
was teratozoospermia 72%, hypospermia 52%, oligozoospermia 28%, and
azoospermia 4%. The median post-thaw total motile count was 0.17 ×
106/vial, and the quality was adequate only for ICSI in 87.7% of the
thawed semen samples. No correlation was found between selected medical
and lifestyle factors and poor semen parameters. Semen quality
is strongly reduced among adolescent transgender females before hormone
therapy and their stored sperm samples are suitable for
intracytoplasmic sperm injection (ICSI) rather than conventional
IVF/intrauterine insemination (IUI).
Findings in sports medicine.
Hilton, Emma N. / Lundberg, Tommy R.
Transgender Women in the
Female Category of Sport: Perspectives on Testosterone Suppression and
Performance Advantage2020 Sports Medicine
https://doi.org/10.1007/s40279-020-01389-3 \cite{Hiltona}Abstract:
Males enjoy physical performance advantages over females within
competitive sport. The sex-based segregation into male and female
sporting categories does not account for transgender persons who
experience incongruence between their biological sex and their
experienced gender identity. Accordingly, the International Olympic
Committee (IOC) determined criteria by which a transgender woman may be
eligible to compete in the female category, requiring total serum
testosterone levels to be suppressed below 10 nmol/L for at least 12
months prior to and during competition. Whether this regulation removes
the male performance advantage has not been scrutinized. Here, we review
how differences in biological characteristics between biological males
and females affect sporting performance and assess whether evidence
exists to support the assumption that testosterone suppression in
transgender women removes the male performance advantage and thus
delivers fair and safe competition. We report that the performance gap
between males and females becomes significant at puberty and often
amounts to 10–50% depending on sport. The performance gap is more
pronounced in sporting activities relying on muscle mass and explosive
strength, particularly in the upper body. Longitudinal studies
examining the effects of testosterone suppression on muscle mass and
strength in transgender women consistently show very modest changes,
where the loss of lean body mass, muscle area and strength typically
amounts to approximately 5% after 12 months of treatment . Thus, the
muscular advantage enjoyed by transgender women is only minimally
reduced when testosterone is suppressed. Sports organizations should
consider this evidence when reassessing current policies regarding
participation of transgender women in the female category of sport.
The British medical journal conducted a large study of people who began
hormone therapy as adults, female to male and male to female. While two
years of cross sex hormone therapy did reduce muscle strength and mass a
speed advantage was retained. Hilton EN and Lundberg T R published a
paper which was well cited that stated a much larger advantage, but this
was latter corrected by the journal due to undeclared conflict of
interest.
Note in the following subsection, as the science is softer all findings
pro and against trans inclusion bear a degree of opinion and
point of view. The above chemical (DNA) and MRI and other laboratory
findings do not have that issue.
Roberts, Timothy A. / Smalley, Joshua / Ahrendt, Dale,
Effect of gender affirming hormones on athletic performance in
transwomen and transmen: implications for sporting organisations and
legislators, 2021 British Journal of Sports Medicine , Vol. 55, No. 11
British Association of Sport and Excercise Medicine p. 577-583
https://doi.org/10.1136/bjsports-2020-102329 \cite{Roberts577}Abstract:
Objective To examine the effect of gender affirming hormones on athletic
performance among transwomen and transmen.Methods We reviewed fitness
test results and medical records of 29 transmen and 46 transwomen who
started gender affirming hormones while in the United States Air Force.
We compared pre- and post-hormone fitness test results of the transwomen
and transmen with the average performance of all women and men under the
age of 30 in the Air Force between 2004 and 2014. We also measured the
rate of hormone associated changes in body composition and athletic
performance.Results Participants were 26.2 years old (SD 5.5) .
Prior to gender affirming hormones, transwomen performed 31% more
push-ups and 15% more sit-ups in 1 min and ran 1.5 miles 21% faster
than their female counterparts. After 2 years of taking feminising
hormones, the push-up and sit-up differences disappeared but transwomen
were still 12% faster. Prior to gender affirming hormones, transmen
performed 43% fewer push-ups and ran 1.5 miles 15% slower than their
male counterparts. After 1 year of taking masculinising
hormones, there was no longer a difference in push-ups or run times, and
the number of sit-ups performed in 1 min by transmen exceeded the
average performance of their male counterparts.Summary The
15–31% athletic advantage that transwomen displayed over their female
counterparts prior to starting gender affirming hormones declined with
feminising therapy. However, transwomen still had a 9% faster mean run
speed after the 1 year period of testosterone suppression that is
recommended by World Athletics for inclusion in women’s events . A
de-identified copy of the data is available from the corresponding
author upon reasonable request.
Hilton, Emma N. / Lundberg, Tommy R.
CORRECTION To: Transgender
Women in the Female Category of Sport: Perspectives on Testosterone
Suppression and Performance Advantage 2021
Sports Medicinehttps://doi.org/10.1007/s40279-020-01389-3 \cite{Hilton}Abstract:
After publication of this article, concerns were raised regarding
potential undeclared conflicts of interest . In light of this
the authors have provided the following statement: EH and TL have given
talks and engaged in the mainstream media and academic press regarding
the biology of sex and how they have concluded that this should impact
sporting categories. All dissemination or engagement, irrespective of
the medium, has been guided by their education, disciplinary training,
and research findings. The authors assert that this does not constitute
a conflict of interest. Rather, it is an essential part of their
academic freedom and their obligation to engage, publicly, in such
discussions.
(See for example:
Harder,
better, faster, stronger: why we must protect female sports by Hilton.
“Male puberty and testosterone. Testosterone, the androgen
driving male physical development, is a wonderful hormone. It is
responsible for advantageous skeletal features that develop during male
puberty, such as increased height, increased bone size and density,
longer limbs,” In short in a field of science where one can select data
in such a way as to create a certain result she selected top tier
athletes and only transgender people who transitioned as adults, post
puberty not during puberty age. The second point is a weakness of all of
the studies in this section and seems to be a standard
practice.
Which is why I searched out the British
Association of Sports Medicines unconflicted study that partially agrees
with hers.
This leaves open the question what of
transgender people who started hormones very young and who have little
or no advantage or disadvantage?) This researchers mind was totally made up before she started, and she also did not disclose this fact to the reviewers.
British Journal of Sports Medicine, Plain language findings and expert opinion.
Transgender individuals have been able to serve openly and have access
to gender affirming hormone therapy in the United States military since
2016. In the Air Force, requests to begin or continue hormonal therapy
are reviewed by a centralized clinic. Of the 222 transgender service
members who requested permission to start or continue treatment, we had
complete fitness and medical data on 46 transwomen and 29 transmen. The
average age was 26.2 with a standard deviation of 5.5 years.
For transmen, there was no significant change in body composition (as
measured by height, weight, and waist circumference) over time. They
were able to perform the same number of sit-ups as cismen prior to
hormone therapy and improved with therapy. Push-ups and run times
reached that of cismen by the 1-year point.
For transwomen undergoing hormone therapy, there was an increase in
weight over time but no change in waist circumference. Push-ups and
sit-ups equalized with ciswomen by the 2-year mark. However,
transwomen still retained an advantage in run times on the mile and a
half run compared to the average time for ciswomen 2 ½ years after
starting medical transition
What does this mean?
In elite level or collegiate athletic competition, where a 1-2%
advantage in speed or strength is often the difference between victory
and defeat, governing bodies need to re-examine guidelines for inclusion
of transgender and other women with elevated testosterone levels and
determine what evidence-based changes are required to ensure a level
playing field. They will need to stand up to legal scrutiny. In youth
and recreational sports there is such a broad range of ability,
training, and development that differences from prior testosterone after
12 months of suppression may not have a meaningful competitive impact
and the benefits of inclusion of all athletes should take priority. When
establishing guidelines for youth and recreational sports, the question
has to be: “What is the best thing for all our athletes?”