The rise of dating apps coupled with the rise of more liberated sexual norms has created numerous opportunities for one of the world's most beloved past times: casual sex. However, the new “hookup culture” has its fair share of haters who ask the question, can casual sex or friends-with-benefits lead to serious relationships? It's no secret that strangers love inserting their opinions into others personal lives — especially when sex is involved. People are judgmental of those who include casual sex in their bedroom habits, labeling them as commitment-phobes and sluts, or shaming their assumed reluctance to be in a “real,” “grown-up” relationship. But casual sex is a common, normal activity. And in an interview with the Washington Post, Helen Fisher, famed biological anthropologist and Chief Scientific Adviser at Match, says that casual sexual relations serve an important purpose, can have wonderful outcomes (when safe and consensual), and can often develop into serious partnerships.

Every year, Match conducts a survey on unwed Americans to gather data on sex and dating habits. This year's survey produced some results that should be very interesting for the casual sex haters out there. The Washington Post reports:

...A quarter of singles have converted a one-night stand into a long-term relationship.The Match study also found that, while online daters have sex more frequently than offline daters, they’re not more promiscuous. Both groups, on average, had the same number of sexual partners. When compared with offline daters, online daters were twice as likely to 'imagine a committed future with someone while on a first date' and 58 percent more likely to want to marry.

Additionally, the annual survey from 2012 found that 44 percent of those surveyed had been in a FWB relationship that evolved into a long-term relationship. In the interview, Fisher attributed these facts to her theory of “slow love,” meaning “singles are looking to make a connection quickly and commit more slowly.” Engaging in sex casually and quickly does not mean that you are closed off to love, Fisher argued, but that you are trying to learn as much about a potential life partner as soon as possible.

She continued, “Early sex means: ‘I’m interested in you. I want to know who you are. I don’t want to spend my life trying to figure out who you are'... “I think people are so scared of divorce that they are putting off marriage until they know everything about this person,” and learning “everything” means learning about compatibility in physical intimacy.

Fisher has similarly written about casual sex and long-term relationships in her book Anatomy of Love. The text referenced a study from 2008 in which 51 percent of 500 surveyed undergrads engaged in casual hookups with the specific goal of finding a serious partner. (As an aside, the data found no difference in response from any gender, men or women.) Friends with benefits and casual sex relationships, writes Fisher, allow you “to learn a great deal about a potential mate before making a formal commitment, marrying and divorcing.” A person's behavior and attitude during sexual activity, she elaborated, helps you learn a lot about another person – like their health, patience, and willingness to listen to your needs. All of which help you to learn enough about someone to want to enter into a long-term relationship with them.

I talked to 22 people whose casual sex relationships have turned into serious, committed, long-term partnerships (and even marriages).

1. Gina, 26

My partner and I met in LA, flirted for a week, and then had a one-night stand. We figured it was going to be just sex. Shortly after, he had to fly back to Australia, where he's from, and we ended up staying in touch. A month later, I sold all my belongings in Boston and flew over to Australia to be with him. It's been 2 years since we've been a couple.

2. Kelly, 22

Our relationship began strictly as friends with benefits. I had recently gotten out of a long relationship and wasn't interested in pursuing something serious. After about a month of frequent hookups though, I felt myself falling for her. A week into these more serious feelings I came clean, and shortly after we began dating officially. We've been together over two years.

3. Taryn, 28

My current boyfriend had just gotten out of an eight year relationship (married for four years) and we started out just having sex. This 'casual relationship' went on for about a year — with unofficial break ups in between. At the year mark of our hooking up, he told me he loved me and we've been together since (three years now — though on and off and rocky).

I was very surprised when the relationship changed because I started to become distant and gave up, even sleeping with another guy I was interested in. I had wanted to be with my current boyfriend a few months into our hooking up. I desired a more serious relationship because I really, really liked him and the sex was really, really good. He was very challenging to me and I liked that at the time (although he chased after me, he's just a difficult person). It's just a connection that the stupid heart wants — not the head. We've been together for three years.

4. Pilar, 27

All of my committed relationships started out as casual sex. It seems to be a cultural norm in my social circle; most of my friends' relationships start out casually rather than as serious dating. This isn't to say that the majority of the people with whom we have casual sex evolve into committed relationships; rather, it generally doesn't happen. However, I have been in situations where my casual sex partner wanted the relationship to become serious, and I did not. Unfortunately, this, at times, has resulted in different levels of physical and psychological violence. The main thing that has catapulted my casual sex relationships into committed relationships is shared experience with someone who was truly my friend and with whom I had great sex. Generally, something has to happen that shakes the foundation of the fundamental relationship. If I get through an emotionally challenging situation and my casual sex partner stays by side and supports me throughout it, the relationship generally evolves into something more meaningful. On the other hand, if my casual sex partners steer clear in my time of need, it can remain as a casual sexual relationship. The longest casual sex partnership that turned into a serious relationship was three years. Then 10 months. A couple two-month relationships. Currently getting more serious with a casual sex partner.

5. Mattie, 18

We were best friends, hooked up with each other on and off for about six months, then developed feelings. Initially, we didn't want a more serious relationship because we wanted to preserve our friendship. But the desire became stronger, and we decided to commit. Our relationship has become serious pretty quickly but is also very steady. We have been together for eight months.

6. Tom, 25

We slept together three times, then she asked if we could be serious so I said OK. We were together for just over a year.

7. Mary, 23

I met my SO at a party and we exchanged numbers and hooked up that night. He left the next morning and texted me later that day. We went on some 'dates' after that and the rest is history. We've been together for 3 1/2 years since that first night and are still going strong. We now live together and are considering marriage.

8. Jason, 37

I was a booty call by my now-wife on Thanksgiving of 2000. We were chatting on AOL Instant Messenger and she said, 'If it wasn't so late, I'd ask you over for a beer.' Sensing what was up, I replied, 'it's not that late.' We hooked up that evening and had casual sex for two more months before we knew we were really into each other. On Easter of 2001, I proposed, and in August of 2002, we were married. We took some 'us' time before having our son in April of 2008. We've now been together for 16 years.

9. Ruby, 28

Most of my long-term relationships started out casually. How do you know you want to be committed to someone unless you get to know them first? My current boyfriend and I were dating for about three months before we 'made it official,' i.e. agreed to stop seeing other people. He wasn't ready for a serious relationship when we met and was very up front about that, but I knew pretty quickly that I wanted more from him than just casual sex. During that time when we were dating but not committed, I definitely dated and slept with other people. But once we had the DTR talk, I cut it off with everyone else. We've been together for three years.

10. Kristine, 23

We actually began seeing each other casually while I was 'seriously' (more so for him than me) dating someone else. I had been working on ending it with the other guy for a while, but guilt over his feelings being hurt kept me there until I met my current partner. My current SO and I were reluctant to start a serious relationship for a while for a multitude of reasons — we have quite a big age difference, I had just gotten out of (and cheated in) a relationship, he just got out of a marriage about a year before we met, and we worked together. We eventually realized how much we had in common — from our sense of humor, to our politics, to our desires for ourselves as people... There wasn't much of an 'a-ha' moment or discussion about becoming an item; we pretty much just started referring to each other as 'boyfriend/girlfriend' about a month and a half into it. We got more 'serious' about 3-4 months later when we both realized our feelings for each other were far deeper than we ever thought our relationship would go. We have been together over four years now and living together for about two years.

11. Caitlin, 23

I had been having casual sex with a friend of mine from high school around the beginning of my junior year of college. Eventually we started to realize that we enjoyed each others company for more than just hooking up, and have now been dating for almost three years.

12. Jane, 20

We met at a video game tournament for about ten minutes and got along well, so we added each other on Facebook. Three days later, we met up halfway for a smaller tournament. I went back with him to his apartment, and things went well. We ended up spending a few days together just hanging out and having sex. I think he was looking for something casual and I was looking for a summer fling, just someone to hang out and have sex with before I went back to college 12 hours away. But we started spending more time talking and really just spending time with each other (in between the sex). He stopped seeing someone else that he had been having casual sex with about a week after we started seeing each other because he knew it was developing into something more. We said 'I love you' about three weeks in, and now six months later I've moved in for a year (working in the industry before returning to school). So our whole relationship just moved really quickly: sex three days after meeting, definitively exclusive two weeks later, 'I love you' about two weeks after that, and I moved in (temporarily) five months later. We are now approaching eight months together.

13. RC, 25

One-night stand off of Tinder turned out to be the most amazing person I have ever met in my life. I had no expectations from the beginning. Will this be just a date? Will we have sex? etc. We really liked each other from our first date. Hung out more and more often. Less than a month together, we began an 'official' relationship. It just felt right. It's almost been one year now. Can't wait for more years to come. I love being a 'Tinder success story.'

14. Heather, 27

Things were casual for about six months, then they got pretty serious pretty fast. We were both really surprised, but everything worked out great. I think that because we started as friends and then transitioned into casually hooking up, all that pretense was gone. We knew who we were as people, so the sex just made things even more intimate and, most importantly, more honest. Having sex with my best friend is probably the best thing on this planet. We are open about everything and there is no judgment. It's going on six years, and we are getting married this year.

15. Ash, 32

I was fresh out of a dead bedroom relationship. It had been a year and I was jonesing. He was recently single as well and we'd always had sexual tension, and he was the perfect booty call for all the aforementioned reasons. One night turned into two, and so on. Conversations got deeper, a bond grew, and suddenly sex turned into feelings. Feelings turned into the most unexpectedly amazing relationship I've ever had! We've been together a little over two years and counting.

16. Rob, 32

I was recently divorced from my high school sweetheart. We had been together for almost 10 years, and I had never been with anybody else. In the few years that followed, I only saw women casually. I wanted to see what was out there. I started having casual sex with a new coworker during my period of casual hook-ups. She was also recently out of a bad relationship and not looking to get caught up in another. Eventually, we became friends. Then, we realized we were spending 24/7 together for months without getting sick of each other. About 6 months after the initial hookup, we were 'dating.' We've been together about five years now, and have two children. Best relationship I've ever had, and I can't imagine better.

17. Sally, 22

Casually hooked up for three months. Decided to try long-distance when I moved because we seemed to just get along. Neither of us were looking for a relationship, but we didn't want to lose the connection we seemed to have. We've been together for three and a half years and are still going strong.

18. Annie, 54

It started as what I thought would be a one-night stand. I didnt think he would contact me again. Months turned to years, years to decades. We just never thought about not being a couple. We've been together 35 years now.

19. Debra, 25

We were f*ck buddies for about three months and then we started dating. I was very surprised by the change because I thought it was just casual for both of us, even though I had started to develop feelings for him. We dated for four years and then got married. Our one year anniversary is in March.

20. Petra

Friends first for six months, then casual sex for six months, then open relationship for three years, then serious open relationship for the last two years. We just got engaged about a week ago. I guess you could say we were both open minded in terms of meeting someone and what the relationship could look like, but neither of us took being in a relationship or in love very seriously for a long time due to wounded hearts and trust issues from prior relationships. Also, neither of us put expectations greater than hoping the other person would be a decent human being. Been together five years and counting.

21. Austin, 30

Had sex with my now ex-girlfriend after meeting her on a drunken night in the International Society at my University. We just kind of started having more and more sex, and in the end we figured, why the hell shouldn't we just be together!? Lasted nine and a half years.

22. Garry, 28

We had dated briefly before. The sex was good but it was the wrong time in life. Stayed friends, a year later we both wanted sex and started hooking up. About three months of that lead to deeper feelings. We've been together for more than a year now.

Want more of Bustle's Sex and Relationships coverage? Check out our video on sex positions for small penises:

Images: Andrew Zaeh/Bustle; Giphy (22)