Birth order and sibling sex ratio in relation to sexual orientation in China

We examined birth order and sibling sex ratio in relation to sexual orientation within a Chinese cultural context. A total of 672 people comprising 160 heterosexual men, 215 homosexual men, 255 heterosexual women, and 42 homosexual women, took part in a web-based survey. Our results showed that as a whole homosexual and heterosexual men had a significantly late position in the birth order of the children in their families, but that the same phenomenon did not apply for homosexual women. In contrast to studies involving Western populations, in this study heterosexual and homosexual men had a significant excess of older sisters, but not older brothers when compared with the norm in a Chinese population. We concluded that the male-preference stopping rule adopted by Chinese parents affected birth order and sibling sex ratio in relation to sexual orientation.