1. This affidavit is provided by
Professor Louis Gooren of the University Hospital of the
Vrije Universtiteit of Amsterdam, the Netherlands.
2. Born in 1943, I am a medical doctor
specialising in the field of endocrinology. Within this
field, diseases related to disorders of sexual
differentiation and the biological process of becoming
man or woman are the focus of my work. In 1988 I was
appointed Professor and assigned to the treatment of
patients who present with gender identity problems as
well as other patients with sexual differentiation
(intersex) disorders who need hormonal and surgical
medical interventions. Over the past 24 years I have
worked at the Gender Clinic of the University Hospital,
which receives about 150 new patients per year.
Approximately 80-90 of them receive actual hormone and
surgical therapy. I have published extensively on these
subjects and enjoy wide and international professional
recognition. I have, by invitation, contributed to text
books of medicine on these subjects. In recent years
Institutions of the Council of Europe have called upon me
to provide expertise in the area of gender problems.
3. Gender Identity Disorder (transsexualism) is
a medical condition and from my work and other research
in this area I now believe that transsexualism is a
disorder of sexual differentiation: the process of
becoming man or woman as we conventionally understand
it.
4. Traditionally it is assumed that sexual
differentiation, the process of becoming man or woman is
completed with the formation of the external genitalia,
the criterion used to assign a new-born child to the male
or female sex. From the beginning of this century it
became clear in laboratory animals that this is not the
endpoint of the sexual differentiation process but that
also the brain undergoes a sexual differentiation into
male and female, largely predicting/correlating with
future sexual and non-sexual behaviour.
5. The process of sexual differentiation takes
place in distinct steps, first the chromosomal
configuration is established, next Gonadal
differentiation, next differentiation of the internal and
external genitalia and finally the differentiation of the
brain into male or female.
6. Normally all steps in the process of sexual
differentiation are concordant (in men, an XY chromosomal
pattern, testis, male internal and external genitalia and
a male brain differentiation being the substrate of male
type behaviour; in women, an XX chromosomal pattern,
ovary, female internal and external genitalia and a
female brain differentiation being the substrate of
female-type behaviour).
7. It is remarkable that in some mammalian
species this process of brain sexual differentiation
takes place after birth. Swaab and Hofman have shown that
one brain structure, that is different between men and
women, becomes only sex-dimorphic between the ages of two
and four years, well after birth and long after
assignment to the male or female sex has taken place.
Nature is not free of errors and the process of sexual
differentiation is no exception. There are human beings
in whom not all traditional criteria of sex are
concordant. They may have some biological characteristics
of one sex and some of the others, a condition known as
intersexed.
8. The human condition requires that new-borns
are assigned to one sex or the other. The social and the
legal system has left no room for intersexed subjects. If
a new-born child presents with an intersexed condition a
medical decision must be made to assign this baby to the
male or female sex. It is now a generally accepted
medical practice to assign an intersexed new-born to that
sex in which the unlucky child, on the basis of medical
expertise and reasonable expectation, will function best.
It is of note that biological characteristics are not
imperative in this decision process. The decision is
based on prognosticated future sexual and nonsexual
functioning. The legal system registers these new-born
children in accordance with the medical decision. Thus,
it is no longer tenable to claim that the genetic or
gonadal criterion determines one's status as male or
female.
9. Some intersex conditions are such that they
can not even be determined at birth and are only
discovered much later at puberty. As such some of our
fellow human beings live (unbeknown to all but their
medical practitioner) their lives as women but with a
male-type XY chromosomal pattern or testis and vice
versa.
10. Sexual and nonsexual brain differentiation
is now accepted as part of the process of becoming male
or female in the mammalian species to which humans
belong. In animal experimentation it is easily possible
to induce a female type of sexual and nonsexual behaviour
in animals that have, up to that final stage of sexual
differentiation, a completely male pattern and vice
versa. Depending on the type of manipulation applied in
the animal experiment, in-between types of behaviour can
also be observed. On the basis of the findings of these
experiments it has been hypothesised that in human
subjects with gender identity problems the sexual
differentiation of their brains has not followed the
pattern predicted by their earlier steps in the sexual
differentiation process (such as chromosomes, gonad,
genitalia) but has followed a pattern typical of the
opposite sex in the final stage of that differentiation
process; as indicated above, a situation that can be
induced in laboratory animals by experimental
manipulation.
11. Generalisations of biological principles
between the different members of the mammalian species
must be done with caution, but they cannot be totally
dismissed. Medicine has progressed enormously by animal
experimentation using this extrapolation from other
mammalian species to the human. The validity of
extrapolation of the sexual differentiation process of
the brain in other mammals to the human has been
corroborated by findings of anatomical and functional
brain differences between males and females, including
the human species. The collection of data in the human
has been, and is, still slow due to obvious ethical
restrictions on collecting brain material for
research.
12. Interestingly, Zhou, Swaab, Gooren &
Hofman, published in 1995 a scientific report that could
demonstrate that in one of the human brain structures
that is different between men and women, a totally female
pattern was encountered in six male-to-female
transsexuals. They were able to show that this was not
due to the transsexuals' previous cross-sex hormone
treatment. These findings showed that a biological
structure in the brain distinguishes male-to-female
transsexuals from men. The findings were published in the
leading scientific journal (Nature) with a rigorous
scientific review process which would not have overlooked
essential scientific biases in the design and
interpretation of the experiment.
13. In conclusion: Since there is evidence that
the sexual differentiation of the brain in the human
occurs (also) after birth it is unavoidable that in
subjects with errors of the sexual differentiation of the
brain, sex assignment takes place after birth, sometimes
much later in their lives since it requires a large
amount of life experience to discover the predicament of
being born in the wrong sex: in other words having sexual
and nonsexual brain patterns that are in contradiction
with the other sex characteristics.
Like other people afflicted with disorders in this
process of sex differentiation, transsexual people need
to be medically rehabilitated so that they can live
acceptable lives as men or women. This decision is not
essentially different from the one made in cases of
intersexed children where assignment takes place to the
sex in which they in all likelihood will function best.
In the case of a intersexed child it is often possible to
tell at birth that the sexual differentiation process has
not taken place in a conventional way and so it is
possible to make that decision to assign a sex through
medical intervention shortly after birth... The decision
to recommend hormonal and surgical treatment for a
transsexual person takes place much later in life and is
based on the conclusion of a thorough psycho-diagnostic
process that concludes that a disorder has occurred in
the process of sexual differentiation and that the person
will benefit from hormonal and surgical sex assignment.
There is never any disagreement that the expenses of sex
assignment at that stage are to be borne by the relevant
health insurance.
