Some of you were asking for further info about the genetics of sex, so here's what I've got. Here's the Amazon link to “Between XX and XY: Intersexuality and the Myth of Two Sexes”. There are some points were I think the book could do a better job of staying away from gender assumptions, but overall it's a great layperson's intro to the uber-complexities of the physiology of what we call “sex”. I got it from my local library, so if your library doesn't have it they'll be able to get it via Interlibrary Loan. http://www.amazon.com/Between-XX-XY-Intersexuality-Sexes/dp/1556527853/ref=sr_1_1?ie=UTF8&s=books&qid=1276656669&sr=8-1 If you really want to dig your teeth into the real research (hi Jen!) here are a couple of citations. There is also a bibliography in the back of the above-referenced book for further research. Clarnette, T., Sugita, Y., & Hutson, J. (1997). Genital anomalies in human and animal models reveal the mechanisms and hormones governing testicular descent. British
Journal of Urology, 79, 99-112. Gravholt, C., Juul, S., Naera, R., & Hansen, J. (1998). Morbidity in Turner syndrome. Journal of Clinical Epidemiology, 51, 147-158.
Kruse, R., Guttenbach, M., Schartmann, B., Schubert, R., van der Ven, H., Schmid, M., & Propping, P. (1998). Genetic counseling in a patient with XXY/XXXY/XY mosaic Klinfelter’s syndrome: Estimates of sex chromosome aberrations in sperm before intracytoplasmic sperm injection. Fertility and Sterility, 69, 482-485.
Book: Levitan, M. & Montagu, A. (1977). A textbook of human genetics (2nd ed). New York: Oxford University Press. Sarah, if you have any more, please share them. Or anyone else too.

]]>