Summary of the evidence provided

The four reference pages provide evidence for the observations I made:

What is transsexualism? | What causes transsexualism? | What helps?

More evidence: Disorders of sex development (DSD)

What do we know after all this research?

  • Brains of transsexuals have features similar to those of the experienced gender (different from those of their biological sex), even before treatment.

  • Distinctive features within the families of transsexuals and distinct genetic features suggest a hereditary component of transsexualism.

  • Transsexualism doesn’t seem to be related with or caused by mental illness.

  • Psychological profiles of transsexuals have features similar to those of the experienced gender (different from those of their biological sex), even before treatment.

  • Hormone exposure before and around birth can shape the gender identity of the brain.

  • Formation of gender identity is independent of the development of physical sex characteristics.

  • Medical treatment and social adjustment can help transsexuals, even cure gender dysphoria.

I don’t think it’s possible to be aware of the facts presented on the pages above and to discriminate against transsexuals. The studies shown give no basis for thinking less of the experiences, feelings, wishes, desires or dreams of people who experience gender dysphoria. Please remember: Everyone is entitled to their own opinions, but they are not entitled to their own facts.[1] If you disagree with my conclusions, please present evidence.

Transsexuals are sane human beings, their happiness and lives carry the same importance as those of other humans. Transsexuals should be able to live open and honest lives, with peace of mind, without shame, harassment or the constant need to defend and explain themselves.

Transsexualism – the summary

The brain is a sexual organ. Brains of women and men show physiological differences in some areas, resulting in distinct feelings of gender identity for woman and men. These physiological differences have been shown to be primarily controlled by differences in hormone levels during perinatal development. Since sexual differentiation of the brain takes place at a different stage of foetal development than sexual differentiation of the genitals, these two processes can be influenced independently of each other. In transsexuals, the development of gender identity and genitals is not aligned. This misalignment has its roots in genetics, epigenetics, gene expression, hormone exposure before birth, and perhaps other, additional factors.

At birth, gender identity is mostly or fully developed and usually stable for life. At some point in their lives, transsexuals experience distress, called gender dysphoria, at the mismatch between their gender identity and their social gender role and/or their physical sex characteristics. These experiences and the feelings to belong to the other gender seem to match our findings and knowledge about sex differences of the brain, gained from studies on brains of non-transsexual males, non-transsexual females and transsexuals. Psychological studies show that transsexuals typically suffer from the distress they experience and from society’s treatment of them.[2] Aside from such factors, transsexuals do not have underlying or associated mental illnesses at a higher rate than non-transsexual people.[3] Transsexuality can be treated by sex reassignment therapy, which improves thequality of life for transsexuals and can cure gender dysphoria.

A short essay on the biological basis for transsexualism can be found here: Biological basis

A personal summary

When starting my research, I never imagined how many studies I would find. Initially, I printed and treasured every single one. Over the years, the numbers kept increasing, and the jigsaw puzzle of the scientific view on transsexualism became ever more complete.

There are many narratives of transsexualism, and many personal experiences. Human identity and human sexual identity are incredibly multi-faceted. Society as well as the medical profession has been changing drastically since the 1960s, shedding prejudices, looking at things more neutrally and objectively. Morality is more and more based on the happiness and suffering of human beings, rather than on traditions and dogma. This has helped in getting a clearer picture of transsexualism, and resulted in removing it from the list of psychopathological diseases. I’m thankful to everybody who has contributed to our society becoming more humane, and hope that the process will continue until discrimination, hate and prejudice have been fully replaced by tolerance and understanding. Hopefully, transsexuality will continue to follow the path of homosexuality towards more normality and acceptance.

In the end, much of the research into the causes of transsexuality doesn’t matter on an individual level. What matters to the individual is:

How do I feel? How is my quality of life compared to normal standards? Is there anything that can be done to improve my happiness, and if so, at what cost (to myself, to others, to society)?

These are the questions important to individuals, and these are the questions society should resolve to answer. Answers should be given weighing the evidence, without prejudice, bias or being influenced by dogma. If we can reach this goal, than sufferers of gender dysphoria will be able to receive optimal support.

We are all human – let’s try together to make the best out of our lives!


This page is the summary of the four main reference pages:

What is transsexualism? | What causes transsexualism? | What helps?

More evidence: Disorders of sex development (DSD)

More references can be found here (articles not directly relevant to the observations discussed on the main reference pages): Other references

A short essay on the biological basis of transsexualism is here: Biological basis

A short discussion regarding possible contradicting evidence is here: Evidence against?

Back to: Gender, sex and all that | Cakeworld Homepage

[1] In this regard, I love the following two quotes – “What can be asserted without evidence can also be dismissed without evidence.” (Christopher Hitchens) and “One’s convictions should be proportional to one’s evidence. Pretending to be certain when one isn’t – indeed, pretending to be certain about propositions for which no evidence is even conceivable – is both an intellectual and a moral failing.” (Sam Harris).

[2] William Gibson’s famous quote fits well here: “Before you diagnose yourself with depression or low self-esteem, first make sure that you are not, in fact, just surrounding yourself with assholes.”

[3] Beautifully expressed by Sarah Seton: “Contrary to current belief, transsexuals are not tormented by their condition: it is their condition, which prompts society to torment them.”

Some disclaimers

Human biology, medicine and especially psychology and psychiatry are not an exact science like mathematics. In nature, things are often multi-faceted and do not fit perfectly to classifications and abstractions. Many things in nature that we can measure are spread out over a bell curve, with most cases close to the average, and extreme cases being rare. This continuum from one extreme to the other should be in kept in mind. Typically, medical facts are about averages only, not about absolute certainties. Does this mean research, trying to learn things about our world, is futile? On the contrary – the more evidence we collect, the closer we get to certainty.

This means we cannot make precise predictions for individuals, only for large groups of individuals. It is very difficult to copy conclusions from the experience of one person to another. However, with the help of studies including many people, we can learn about typical development and characteristics and find answers on what interventions can help.

On forums for transsexuals, specific questions are often answered with personal experience, or facts derived from averages, plus the caveat “your mileage may vary”. Everybody is different and unique.

Bell curve

The sample picture on the left shows two typical bell curves illustrating male and female traits. As you can see, there is a small, but noticeable difference between the averages. However, the traits of individuals overlap greatly.

The author of the blog “Sugar and Slugs” did a lot of work to use data from real studies to illustrate sex/gender differences (full article on

The diagrams here illustrate:
– female and male heights
– male and female finger ratios
– female and male BSTc neuron numbers

Body heights

Finger ratios

Neuron numbers