I'd like to see the same thing, but for your position. And I'm aware of the studies trotted out, I think we both know they were hyped into something they are not by the media.
Here are some to get you started.
[Influence of genetic factors on human sexual orientation. Review]
RodrÃguez-Larralde A, Paradisi I.
Invest Clin. 2009 Sep;50(3):377-91. Review. Spanish.PMID: 19961060 [PubMed - indexed for MEDLINE]
Review and theory of handedness, birth order, and homosexuality in men.
Blanchard R.
Laterality. 2008 Jan;13(1):51-70. Review.PMID: 18050001 [PubMed - indexed for MEDLINE]
The neurodevelopment of human sexual orientation.
Rahman Q.
Neurosci Biobehav Rev. 2005;29(7):1057-66. Epub 2005 Apr 25. Review.PMID: 16143171 [PubMed - indexed for MEDLINE]
Sexual differentiation of the human brain: relevance for gender identity, transsexualism and sexual orientation.
Swaab DF.
Gynecol Endocrinol. 2004 Dec;19(6):301-12. Review.PMID: 15724806 [PubMed - indexed for MEDLINE
The etiology of anomalous sexual preferences in men.
Quinsey VL.
Ann N Y Acad Sci. 2003 Jun;989:105-17; discussion 144-53. Review.PMID: 12839890 [PubMed - indexed for MEDLINE]
Fraternal birth order and the maternal immune hypothesis of male homosexuality.
Blanchard R.
Horm Behav. 2001 Sep;40(2):105-14. Review.PMID: 11534970 [PubMed - indexed for MEDLINE]
http://www.ohsu.edu/pcmonline/docs/Homosexuality.pdf