The researchers determined partnered men and women had the lowest overall testosterone levels, while polyamorous men and women both had higher amounts of testosterone than single or monogamously partnered individuals.
The team of scientists theorizes the hormone may be involved in "bond maintenance" and in preparing the individual for competition.
Such competition may be either external, as in fending off other suitors, or internal, as in strengthening the person in preparation for a possible child. Other studies have demonstrated that sperm from different men compete with each other to fertilize the egg, although women also appear to exert some influence over which sperm achieves the feat.
Peter Gray, assistant professor in the Department of Anthropology and Ethnic Studies at the University of Nevada, Las Vegas, has also conducted studies on testosterone as it relates to partnerships and sexual activity.
Gray told Discovery News that the two new studies "are interesting, because they provide another nuance to previous work in this area."
He added, "These studies show that our social relationships and gonads have their own relationships."
In the future, with additional funding and research, van Anders hopes the findings may lead to treatments for clinical conditions related to sexual activities, such as loss of desire and energy.
