And some more, I don't pretend to understand it all, but get the gist,, Perhaps one day, DNA tests will be a vital
part in confirmation of Transsexualism along with the psychiatric evaluations The problem I could see from this would be the denial of treatment if the DNA proved otherwise.
32. Other studies also support the hypothesis that there are psychoneuroendocrinological
links in the development of transsexualism, that is, that the endocrine environment
impacts on the neural organisation of potentially sex dimorphic areas of the brain;
these, in turn, influence the psychological identification as male or female (Gooren,
1990; Swaab and Hofman, 1995; Zhou et al., 1995; Diamond, 2002; Kruijver et al.,
2000; 2002; 2003). Sex differentiation of the mammalian brain has been shown to be
initiated during fetal development and continues after birth (Phoenix et al, 1959;
Kawata, 1995; Chung et al., 2002). It is also postulated that the hormonal effects on
the brain occur at several critical periods of sex differentiation during which gender
identity may be established. So, at present, although the exact mechanism is
incompletely understood, it is hypothesised that an atypical hormone environment at a
critical time in the organisation of the fetal brain may be associated with an
inconsistent gender outcome (Kruijver, 2004).
33. It is postulated that, in those who experience severe gender dysphoria, the sex
differentiation of their brains has not followed the pattern usually predicted by the
earlier steps in the differentiation process (such as the chromosomes, genitalia and
gonads) “but has followed a pattern typical of the opposite sex in the final stage of
that differentiation process” (Gooren, 1999; Gooren and Kruijver, 2002). This
hypothesis is substantially supported by two important studies on post-mortem brains,
including those of trans individuals (Zhou et al., 1995; Kruijver et al., 2000).
34. These studies followed others that found several sex-dimorphic nuclei in the
hypothalamic and other areas of the brain (Allen & Gorski, 1990; Le Vay, 1993;
Swaab et al., 2001). Of particular interest, in regard to transsexualism, is the sexdimorphic
region called the central subdivision of the bed nucleus of the stria
terminalis (BSTc). This nucleus appears to become fully volumetrically sex
differentiated in the human brain by early adulthood. In human males the volume of
this nucleus is almost twice as large as in females and its number of neurons is almost
double (P <
.006) (Zhou et al.,1995; Kruijver et al., 2000; Chung et al., 2002). The
Kruijver et al. study found that in the case of trans women (n=7), the size of this
nucleus and its neuron count was in the same range as that of the female controls
(n=13) and, therefore, women in the general population. When all the subjects were
included, the neuronal differences between the groups were found to be highly
significant. In the only available brain of a trans man, the volume and structure of this
nucleus was found to be in the range of the male controls (n=21) and, therefore, men
in the general population. The latter is not a significant result, but in the context of the
overall findings, it leads to the hypothesis that this male-like BSTc will be present in
other trans men as well.