AUSTIN - Men most often regret not having sex with more people while women frequently regret having sex with the wrong partner, according to a recently released study.

The study from researchers at the University of Texas and University of California-Los Angeles aimed to show that the feeling of regret is part of the evolutionary process when it comes to reproduction, the University of Texas said on Monday.

"For men throughout evolutionary history, every missed opportunity to have sex with a new partner is potentially a missed reproduce opportunity - a costly loss from an evolutionary perspective," said Martie Haselton, a UCLA social psychology professor who worked on the study.

The three main regrets for men: being too timid to approach a possible partner, not being more sexually adventurous when young and not being more sexually adventurous in their single days.

The main regrets for women include losing their virginity to the wrong partner, cheating on a present or past partner and moving too fast sexually.

"The consequences of casual sex were so much higher for women than for men, and this is likely to have shaped emotional reactions to sexual liaisons even today," Haselton said in a statement.

More women than men included "having sex with a physically unattractive partner" as a top regret.

The report was based on three studies with a total of about 25,000 people and the findings were published in the current issue of the Archives of Sexual Behavior, an academic journal.

6 top sex-drive killers of men and women

The things (and the things that you do) that can kill your mood for sex.

Click on the thumbnails to find out more.

(Source: Simpler Her, March 2013; Photos: TNP, ST, Nuyou)