Scientists have now found the reason behind why women like to cuddle after sex and men would rather have a fag or a drink.
A new study on the after-sex behaviours has suggested that women were more likely than men to initiate and place greater importance on behaviours linked to intimacy and bonding with both long and short-term partners.
Men were more likely to engage in behaviours that were "extrinsically rewarding" or increased the likelihood of further coital acts.
"The vast majority of the research on the evolutionary psychology of human reproduction focuses on what's before and leading up to sexual intercourse," said Susan Hughes, author of the study.
"But reproductive strategies don't end with intercourse; they may influence specific behaviours directly following sex," she said.
There are a number of elements of reproduction happening after the act itself, she pointed out, including bonding, future relationship intentions (and possible continued sexual activities), sperm retention and competition, mate guarding and the possibility of fertilization.
"We predicted that post-coital considerations are experienced quite differently by men and women due to divergent adaptive reproductive strategies," she said.
The study examined the responses to an online questionnaire given to 170 people.
"Females placed an overall great importance than did males on all five items measured: intimate talking, kissing, cuddling and caressing, professing their love for their partner and talking about the relationship after sex," said Hughes.
"In contrast, men placed more importance on gaining extrinsic rewards after sex (e.g. drinking or smoking, eating, or asking partner for favors). Men also placed more importance on continuing sexual activity than did females," she added.
According to the study, men were more likely to initiate kissing before sex, while women were more likely to initiate kissing after sex.
Additionally, females thought intimate talking and discussing the relationship was more important before sex than after. Men's opinions remained constant for both before and after sex.
One thing both men and women could agree was the importance of saying "I love you" to a long-term partner after sex.
The findings were published in the Journal of Sex Research.