to the fullest extent possible. With the exception of the internal and external genitalia, sex characteristics are contingent of the biological effects of the respective sex steroids. Hormonal reassignment has therefore two aims: 1) to eliminate, in so far as possible, the hormonally induced secondary sex characteristics of the natal sex and 2) to induce those of the new sex.Biologic females treated with testosterone experience the following permanent changes: a deepening of the voice, clitoral enlargement, mild breast atrophy, increased facial and body hair and male pattern baldness. Reversible changes include increased upper body strength, weight gain, increased social and sexual interest and arousability, and decreased hip mass.Hormonal Replacement Therapy (HRT)Hormones are long-range chemical messengers of the body, manufactured and controlled by the endocrine system. The hypothalamus produces gonadotropin-releasing hormone (GnRH). This signals the anterior pituitary gland to synthesize and release luteinizing hormone (LH). To a lesser degree, GnRH also triggers the synthesis and release of follicle stimulating hormone (FSH). Subsequently, LH and FSH signal the gonads (ovaries in females, testes in males) to synthesize and release hormones that cause differentiation of the body tissue into female or male form: estrogen, progesterone, and testosterone. A small quantity of testosterone is also produced by the adrenal gland. Proportionally, females have more estrogen and progesterone than males; males have more testosterone. Various testosterones are collectively known as androgens. They excite androgenic receptors, causing the body to differentiate into male form and function. Natural and synthetic testosterones are hereafter referred to simply as androgens. Anti-hormones can be useful in transsexual hormone therapy because they block hormone action or production. The basic mechanisms are: Estrogen receptor antagonist: blocks the act...
