Disclaimer: This piece makes heterosexist assumptions in the interest of simplicity.
The social science research
According to Donna Freitas, who wrote a book called Sex and the Soul, a hook-up is any sexual encounter that is unplanned, casual and has no promise of a future. She says that it often involves alcohol, and no other forms of intimacy. No Strings Attached (NSA) sex is another term for having sex with nothing (strings) bonding the two parties together.
There is a culture of 'hooking up' that has become popular among college students and young adults. There are websites that cater to people who are not interested in a relationship other than a brief sexual encounter, or are interested in an ongoing sexual relationship with no promise of a future or of anything more than the sex. As we delay marriage and have the benefits of contraception, casual sex fills in the gap between the onset of sexual desire and a long-term relationship.
Lisa Wade, a sociological professor who authors a blog called Sociological Images, conducted a small study and found that women who hooked up did feel the freedom to say yes to sex but they did not feel like equals to men in the modern sexual culture of young adults. Although both women and men reported feeling dissatisfied with a lot of the hooking up they did do, women were particularly dissatisfied, probably related to the fact that their pleasure was secondary to the man's.
Another study recently released by Julie A. Reid, Sinikka Elliot and Gretchen R. Webber, studied 273 students and found that though students perceive sexual desire to be equal in both men and women, they believed that women were just as capable as men of having no strings attached sex. But a double standard applied: Women still needed to manage their sexual encounters to avoid being stigmatized and marginalized for their sexual choices, whereas men had no such issue.
Lastly, Catherine M. Grello, Deborah P. Welsh, and Melinda S. Harper reported on a study of no strings attached sex in colleges students in the Journal of Sexual Research. In their literature review they reported on studies that showed that although both men and women want emotional commitment, commitment was more important to women, and women often have sex hoping that things will evolve into a relationship. They found an association between depression in women and casual sex that was stronger than that found for men.
This is a relatively new field of study and clearly the jury is out on how men and women experience casual sex. So I will revert to the basic question of nature versus nurture. If we're not so clear on the social aspects, let's explore the biological context.
Post-feminism women feel that they can behave like men sexually. Perhaps they can, but women ARE different than men.
When women have sex, oxytocin gets released because of the evolutionary drive to attach to someone who may be the potential father of a possible child. Evolution is not switched off because the pill, IUD, condoms and all other forms of contraception came into existence. Oxytocin makes women want to bond. Can our psychology override our biology? Men's bodies release testosterone which drives them off to go find some other women with whom to spread their biological material. So it seems that biology grows strings when women have sex.
So what to do?
Of course, being higher order beings, we can control our emotions and our biological urges. However, this takes work, experience and maturity. And the impact of wanting to bond with someone who does not want to bond can leave women feeling disappointed, confused and sometimes hurt.
Should women have casual sex? Well, 'shoulds' are not applicable to sex. Whatever works between consenting adults is not to be judged by me. However, from my own personal experience, most women cannot have a sexual encounter and not feel hurt if a man does not call again and is clear he has not intention to do so.
Does the increase in the alcohol consumption of women have anything to do with the increase in casual sex? If she cannot do it sober perhaps she shouldn't be doing it at all. Liquid courage to have sex often ends in liquid tears afterward. In college culture, hooking up is often fueled by alcohol which implies that under sober circumstances women would choose not to have sex with a casual acquaintance.
It should be noted that in the Reid, Elliot and Webber study neither men or women seem to be particularly happy with NSA sex but women are less happy. Perhaps humans were not meant to couple in such a way and though the delay of long-term relationships farther into adulthood, and the science of contraception may have given us new choices, it could be that humans—both men and women—were meant to couple in the context of more meaningful, 'safer' relationships.
That said, when it comes to sex, if it feels good do it (safely), but if it does not feel good then why bother?