STUDY: Gay Sex Helps Humans Bond and Survive

A new study indicates that same-sex attraction may have evolved to benefit society.

Diana Fleischman, MD, and a research team at the University of Portsmouth in England have published preliminary research in the Archives of Sexual Behavior, which provides evidence that the purpose of sex extends beyond procreation -- it also forms bonds between people that are beneficial to survival. Thus, sex between people of the same gender may have played a crucial role in forming alliances and friendships that have benefited humanity throughout its history.

To arrive at this conclusion, Fleischman measured the levels of progesterone -- a hormone known to be associated with a motivation toward forming relationships -- in men and women in a series of tests. Through an online questionnaire that measured same-sex attraction in 244 participants with queries like "The idea of kissing a person of the same sex is sexually arousing to me," researchers found that in women, higher levels of progesterone were linked to an increased openness to sexual behavior with people of the same gender. The hormone levels were measured through samples of saliva.

Similarly, men were asked to complete one of three possible word completion games with words that were affiliated with either sex, friendship, or neutrality. The study found that men with the highest progesterone levels who opted for the friendship puzzle, which reminded them of the importance of bonds with other men, had, as a University of Portsmouth news release words it, "41 per cent greater homoerotic motivation."

"From an evolutionary perspective, we tend to think of sexual behavior as a means to an end for reproduction," Fleischman noted in the report. "However, because sexual behavior is intimate and pleasurable, it is also used in many species, including non-human primates, to help form and maintain social bonds. We can all see this in romantic couples who bond by engaging in sexual behavior even when reproduction is not possible."

"The results of our study are compelling because using two very different methods, they arrived at the same conclusion," she continued. "Women were more likely to be motivated to think about homosexual sex when their levels of progesterone were higher. Compared to a control group, men's homoerotic motivation was not increased by priming them with sex but thinking about friendship and bonding caused a measurable change in their attitude to the idea of having sex with other men."

Moreover, studies have found similar behavior in other mammals like apes, which may also engage in sex with others of the same gender in order to strengthen relationships.

"Humans are among a group of animals who have sex for many reasons, not just to reproduce," Fleischman concluded. "Reasons can include pleasure, a reward, a way of saying 'please be nice to me' or exerting dominance. It's very complex, but it's clear there's a continuum between affection and sexuality and sexuality is fluidity, that is, the ability to engage sexually with those of the same sex or the opposite sex is common. In humans, much, if not most of same-sex sexual behavior occurs in those who don't identify as homosexual."