| Transsexual feelings are strong, in part, because they have a biological basis. 变性的感觉是很强烈的，部分是有他们生物学上的根据的。 They are caused by different factors including a critically timed hormone released by the mother during gestation. 造成这种情况的因素不尽相同，其中包括母亲怀孕的关键时刻释放出来的荷尔蒙。 Other confirmation of transsexuality's biological roots are its existence in cultures all over the world throughout time. 变性欲有其生物学根源的另一实证是它长期以来始终存在于世界各地的文化之中。 From Greece to Africa, from India to North America, transsexuals held a sacred place in primitive societies and were allowed to live as the gender of their choosing. 从希腊到非洲，印度到北美，变性欲者在原始社会中具有神圣的地位，并且还被允许按照他们选择的性别来生活。 Modern classification and medical treatment of transsexuals began in 1930 with the first sex change operation. 现代对变性欲者的分类和医学治疗始于1930年的首次变性手术。 Still, for decades afterward, the mainstream medical community saw transsexuality as a mental disorder. 尽管如此，在几十年后，主流医学界仍将变性欲视为一种精神错乱。 After the ‘60s, however, studies supported a biological cause. 然而，60年代以后，研究结果却证实变性欲是因为生物学上的原因。 Scientists also learned that transsexuality is evenly split between males and females, and that transsexuals may be straight, gay, bisexual, or asexual. 科学家也发现变性欲平均分布于两性之间，而且变性欲者可能是异性恋、同性恋、双性恋，或无性者。 |
