Anti-mullerian hormone receptor type 2 transcript variants encoding different isoforms have been identified. [provided by RefSeq, Sep 2009]. Anti-mullerian hormone receptor type 2 Anti-Mullerian hormone receptor type 2 is a protein that in humans is encoded by the AMHR2 gene. This gene encodes the receptor for the anti-Mullerian hormone (AMH) which, in addition to testosterone, results in male sex differentiation. AMH and testosterone are produced in the testes by different cells and have different effects. Testosterone promotes the development of male genitalia while the binding of AMH to the encoded receptor prevents the development of the mullerian ducts into uterus and Fallopian tubes. Mutations in
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