Transgender hormone therapy (male-to-female) medical professional. Inducers of CYP3A4 and other cytochrome P450 enzymes can reduce the effects of MTF HRT. A variety of different sex-hormonal medications are used in feminizing hormone therapy for transgender women. These include estrogens to induce feminization and suppress testosterone levels; antiandrogens such as androgen receptor antagonists, antigonadotropins, GnRH modulators, and 5α-reductase inhibitors to further oppose the effects of androgens like testosterone; and progestogens for various possible though uncertain benefits. Estrogens are the major sex hormones in women, and are responsible for the development and maintenance of feminine secondary sexual characteristics, such as breasts, wide hips, and a feminine
Fraternal birth order and male sexual orientation fraternal birth order (or the underlying variable it reflects) may be the first universal factor to be identified in development of same-sex attraction in males. Bearman and Brückner (2002) argued that studies showing a fraternal birth order effect have used nonrepresentative samples and/or indirect reports on siblings' sexual orientation. Their analysis, focusing on opposite-sex twins, did not find an association "between same-sex attraction and number of older siblings, older brothers, or older sisters". A study by Francis (2008), using the same Add Health survey but with broader analysis, saw a very weak correlation of male same-sex attraction with having multiple