How ever I am commanded to attempt to provide you with some basic understanding of the hows and whys those who you understand to be Transsexual a term housed within the larger umbrella term known as Transgender. First to understand either term you must know that the term Transgender is a large umbrella term that includes several other sexuality types the term is primarily used in the field of psychology a term that Transsexuals are trying to separate themselves from as so not to be confused with cross dressers, Transvestites, drag queens or drag kings Transsexuals are quite different from those other terms. For now I will focus on Transsexuals as they are the ones seeking sex affirmation surgerys the exact medical scientific cause of Transsexualisim is not defined though a prevailing cause is suggested more and more. In human history Transgender people have been recorded first nations people of north America recognized them and some tribes revered them while others shunned them Transgender people existed in western and eastern Europe as well as north and south Asia to the African continent. Transgender people then were exposed to natural compounds substances like soy beans wild yams licorice root and many other natural bio identical hormones these bio identical hormones are of course estrogen and progesterone if taken insufficient quantity by a pregnant mother she would cause developmental harm to the fetus in the womb. Moving ahead to post industrial revolution we have now man made substances that are bio identical to human hormones these man made and natural substances are called endocrine disruptors these substances not only compete with the hormones required by developing fetus’s but can replace them. A male fetus that begins development suddenly has the hormone testosterone replaced by bio identical synthetic estrogen contained in a substance like BPA or bisephenol A a plastic substance banned by the FDA for its estrogenic effects would certainly develop sexual reproductive issues. The same can be said of female fetus’s endocrine disruption is one suggested cause and is seriously being looked at. To develop properly a human fetus needs specific hormones at specific amounts at specific times for specific duration a deviation in any of those criteria you will have a fetus with certain defects. Stress on a mother alone is enough to alter proper fetal development.