Obviously. Which studies? Specific genetic sequences, chemical pathways and mechanisms. Not a blanket statement that “science” supports it.
What empirical evidence do you have? Preferably by people whose livelihood doesn’t depend on work with that group
Provide cold, hard empirical facts.
You’ll find some of them in:
Male-to-female transsexuals show sex-atypical hypothalamus activation when smelling odorous steroids. by Berglund et al
Cerebral Cortex 2008 18(8):1900-1908;
Male–to–female transsexuals have female neuron numbers in a limbic nucleus. Kruiver et al
J Clin Endocrinol Metab (2000) 85:2034–204
Sexual differentiation of the human brain: relevance for gender identity, transsexualism and sexual orientation. Swaab
Gynecol Endocrinol (2004) 19:301–312.
A sex difference in the human brain and its relation to transsexuality. by Zhou et al
Nature (1995) 378:68–70.
A sex difference in the hypothalamic uncinate nucleus: relationship to gender identity. by Garcia-Falgueras et al
Brain. 2008 Dec;131(Pt 12):3132-46.
Discordant Sexual Identity in Some Genetic Males with Cloacal Exstrophy Assigned to Female Sex at Birth by Reiner and Gearhart,
N Engl J Med. 2004 January 22; 350(4): 333–341.
The role of androgen receptors in the masculinization of brain and behavior: what we’ve learned from the testicular feminization mutation. Zulago et al.
Horm Behav 53:613-626
White matter microstructure in female to male transsexuals before cross-sex hormonal treatment. A diffusion tensor imaging study. - Rametti et al,* J Psychiatr Res*. 2010 Jun 8.
Regional cerebral blood flow changes in female to male gender identity disorder. - Tanaka et al,
Psychiatry Clin Neurosci. 2010 Apr 1;64(2):157-61.
“Prenatal hormones versus postnatal socialization by parents as determinants of male-typical toy play in girls with congenital adrenal hyperplasia” Pasterski VL, Geffner ME, Brain C, Hindmarsh P, Brook C, Hines M
Child Dev 76(1):264-78 2005
AMH and AMH receptor defects in persistent Müllerian duct syndrome by Josso et al
Human Reproduction Update, Volume 11, Number 4, July 2005 , pp. 351-356(6)
Disorders of sex development expose transcriptional autonomy of genetic sex and androgen-programmed hormonal sex in human blood leukocytes. by Holterhus et al
BMC Genomics. 2009 Jul 1;10:292.
Male Gender Identity in Complete Androgen Insensitivity Syndrome by T’sjoen et al.
Arch Sex Behav. 2010 Apr 1.
Biological and Psychosocial Correlates of Adult Gender‐Variant Identities: a Review by J.F.Veale & D.E.Clarke,
Personality and Individual Differences (2009) 48(4), 357-366
Sexual differentiation of the human brain in relation to gender identity and sexual orientation D.Swaab & A.Garcia-Fulgaras
Functional Neurology, Jan-Mar 2009:
Changing your sex changes your brain: influences of testosterone and estrogen on adult human brain structure by Pol et al,* Europ Jnl Endocrinology*, Vol 155, suppl_1, S107-S114 2006
Neuroimaging Differences in Spatial Cognition between Men and Male-to-Female Transsexuals Before and During Hormone Therapy by Scoening et al J
Sex Med. 2009 Sep 14.
Regional gray matter variation in male-to-female transsexualism. by Luders et al
Neuroimage. 2009 Jul 15;46(4):904-7.
Clinical Implications of the Organizational and Activational Effects of Hormones M.Diamond
Hormones and Behavior 55 (2009) 621–632
Dichotic Listening, Handedness, Brain Organization and Transsexuality Govier et al International Journal of Transgenderism, 12:144–154, 2010
Atypical Gender Development: a review Besser et al* International Journal of Transgenderism* 9(1): 29-44. 2006
Biased-Interaction Theory of Psychosexual Development: “How Does One Know if One is Male or Female?” M.Diamond
Sex Roles (2006) 55:589–600
Specific Cerebral Activation due to Visual Erotic Stimuli in Male-to-Female Transsexuals Compared with Male and Female Controls: An fMRI Study by Gizewski et al
J Sex Med 2009;6:440–448.
None of that involves genetics only anomalies in the hormonal environment in the womb. Animal experiments show similar neurological effects the syndrome is completely repeateable. Farmers have observed freemartin heifers and other neurologically intersexed livestock since time immemorial so it is no great stretch to believe that humans might not be uniquely exceptional and unlike all other mammals ever examined so subject to neurological cross-sexing and thus instinct and identity
The complete list of references is too long but you could start with looking at these as they were used by Prof Sid Ecker in his presentation to the American Psychiatric Association on the biological basis of transsexuality in 2009:
Arnold, A. P. (2004). Sex chromosomes and brain gender.
Nat Rev Neurosci 5,
701-8.
Arnold, A. P., Xu, J., Grisham, W., Chen, X., Kim, Y. H., & Itoh, Y. (2004). Minireview:
Sex chromosomes and brain sexual differentiation.
Endocrinology 145,
Bentz, E. K., Hefler, L. A., Kaufmann, U., Huber, J. C., Kolbus, A., & Tempfer, C. B.
(2008). A polymorphism of the CYP17 gene related to sex steroid metabolism
is associated with female-to-male but not male-to-female transsexualism.
Fertil Steril 90, 56-9.
Bentz, E. K., Schneeberger, C., Hefler, L. A., van Trotsenburg, M., Kaufmann, U.,
Huber, J. C., & Tempfer, C. B. (2007). A common polymorphism of the
SRD5A2 gene and transsexualism.
Reprod Sci 14, 705-9.
etc