Although seemingly more promising than psychological theories, biologically based ones struggle to explain sexual orientation. While hormones can influence masculine and feminine behavior, they do not show any clear impact on sexual orientation; it is important to appreciate that gender role inversion is not linked to homosexuality. Based on early research, brain structures and namely the hypothalamus, possibly underlie homosexuality, but none has stood up to repeated research. Then there is the possibility of “gay” genes that has also come up empty handed. Biological explanations have been proposed to explain the evolutionary paradox: How could homosexuality not leading to reproduction ever have evolved? These theories often take the perspective that even though the reproductive success of gay men (they do not consider gay females) is diminished, the reproductive success of relatives is enhanced. For example, gay men by being altruistic help relatives succeed. Really? There is absolutely no evidence that gay men are more altruistic than the average person, and we can all think of gay men we know who are as selfish as the rest of us. Another evolutionary perspective is that “gay” genes (recall none identified) assist the man in being a better parent, such as being more nurturing. Beyond diminishing the “masculine” father role, this approach entails gender role inversion found to be false. Biological perspectives then end up no better than psychological ones at explaining homosexuality (see the Biological Theories chapter of Outing The TRUTH About Sexual Orientation), strongly suggesting that we are way off the mark in assuming that homosexuality is a real entity.