Older brothers, sexual orientation, and maternal immune reactivity

哥哥、性取向和母体免疫反应

• 批准号: 371602-2010
• 负责人: Bogaert, Anthony
• 金额: $ 3.06万
• 依托单位: Brock University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Group
• 财政年份: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=461285
• 关键词: Older; brothers; sexual; orientation; maternal

We have found evidence that gay men have a greater number of older brothers than do heterosexual men. This "older brother" effect has been replicated numerous times. Recently, we have found strong evidence that the older brother effect is of prenatal origin. Although there is no direct support for the exact prenatal mechanism, we believe that the most plausible explanation is immunological in origin, i.e., a mother develops an immune reaction against a substance important in male fetal development during pregnancy, and that this immune effect becomes increasingly likely with each male gestation. This immune effect is hypothesized to cause an alteration in (some) later born males' prenatal brain development. The target of the immune response may be molecules on the surface of male fetal brain cells (e.g., including in the anterior hypothalamus). Antibodies might bind to these molecules and thus alter their role in typical sexual differentiation, leading some later born males to be attracted to men as opposed to women. There is evidence that mothers of boys can indeed develop an immune response to one substance (i.e., H-Y antigen) important in male fetal development, and that this immune effect becomes increasingly likely with each additional boy to which a mother gives birth. However, no evidence exists of a maternal immune response to other male-specific substances important in male fetal development (e.g., male-specific proteins), nor any evidence of a maternal immune response in men's sexual orientation development. Thus, to expand research on maternal immune reactivity, we will examine whether young mothers of boys are more likely to develop an immune reaction to a number of male-specific substances (e.g., male-specific proteins) than are young mothers of girls. We will also examine whether there is evidence that mothers of gay men (versus of mothers of heterosexual men), particularly those who had previous male pregnancies, may have had an immune reaction to male specific substances important in fetal development. Immune assays targeting male-specific substances will be developed. Then, using blood drawn from the mothers, the assays will test for evidence of immune reactivity to these substances.

我们发现有证据表明，男同性恋者比异性恋者有更多的哥哥。这种“老大哥”效应已经被复制了无数次。最近，我们发现了强有力的证据，哥哥效应是产前起源。虽然没有直接支持确切的产前机制，但我们认为最合理的解释是免疫学起源，即，母亲在怀孕期间对一种对男性胎儿发育很重要的物质产生免疫反应，这种免疫效应随着每次男性怀孕而变得越来越可能。这种免疫效应被假设会导致（一些）后来出生的男性产前大脑发育的改变。免疫应答的靶标可以是雄性胎儿脑细胞表面上的分子（例如，包括在前下丘脑中）。抗体可能与这些分子结合，从而改变它们在典型的性别分化中的作用，导致一些后来出生的男性被男性吸引，而不是女性。有证据表明，男孩的母亲确实可以对一种物质产生免疫反应（即，H-Y抗原）在男性胎儿发育中的重要性，并且这种免疫效应随着母亲生育的每一个额外的男孩而变得越来越可能。然而，没有证据表明母体对男性胎儿发育中重要的其他男性特异性物质（例如，男性特异性蛋白），也没有任何证据表明男性性取向发展中的母体免疫反应。因此，为了扩大对母体免疫反应性的研究，我们将研究男孩的年轻母亲是否更有可能对一些男性特异性物质产生免疫反应（例如，男性特异性蛋白质）比女孩的年轻母亲。我们还将研究是否有证据表明，男同性恋者的母亲（与异性恋者的母亲相比），特别是那些以前有男性怀孕的母亲，可能对胎儿发育中重要的男性特异性物质有免疫反应。将开发针对男性特定物质的免疫测定法。然后，使用从母亲身上抽取的血液，检测将测试对这些物质的免疫反应的证据。