Being part of voluntary services not only makes people feel good about them, but also increases their chances of having sex, according to a new study conducted by researchers from the University of Nottingham and Liverpool John Moores University.

The study has been published in the BMC Evolutionary Biology.

Researchers have found that noble behavior in both men and women can make them more attractive to a potential sexual partner. It was particularly stronger for men, where women favored them in both one-night stands and long-term relationship.

The team arrived at a conclusion after conducting experiments on 32 heterosexual women and 35 heterosexual men. The researchers asked the participants to score the attractiveness of the opposite sex based on a list of characteristics and activities.

They found that both sexes favored those who were involved in charitable events for long term relationships. When rating partners for a brief sexual encounter, women were still attracted to men who exhibited altruism. However, it was the opposite for men.

"At first glance, it's difficult to see how natural selection could favour behaviours that involve investing significant time and resources to help others at a cost to oneself," said Dr Freya Harrison, a Research Fellow in The University of Nottingham's Life Sciences Centre for Biomolecular Sciences. "We now know that "altruistic" helping can actually increase evolutionary fitness in various ways - people might preferentially help their relatives, with whom they share genes, or they might target their helping toward others who are likely to reciprocate in the future."

'We're not sure whether being helpful to others signals that you're more likely to be a good parent who helps your partner with the work involved in raising children, or whether it might be a signal that you carry "good genes" that will produce healthy children,' said Harrison. 'Having the energy and ability to help others might be a show of vigour, rather like a peacock's tail. It would be really interesting for future work to try to tease these two possibilities apart.'

Tags Sex, Blood, Donation