Are some people just wired to be single? There are many different factors that can determine whether or not someone will fall in love. But a 2014 study published in the journal Scientific Reports wanted to see if genetics had anything to do with it. When the average person falls in love, serotonin levels in the brain usually increase in order to influence bonding and affection. But there is a gene, 5-HT1A, that decreases serotonin levels and makes having close relationships uncomfortable for some. So researchers tested hair follicle cells from over 500 college students. They also asked each participant about their relationship status. As they found, people carrying the G allele, which influences the expression of the 5-HT1A gene, were more likely to be single.

As it turns out, opposites don't really attract. A 2017 study published in the journal Nature Human Behaviour found that we actively seek out partners who are similar to us. Researchers looked at over 24,000 couples and found a strong link between an individual's genetic markers for height and the actual height of their partner. They also found similar results when comparing body mass indexes, but the link wasn't as strong. Researchers believe that this is evidence of "assortive mating" in humans, which is a type of sexual selection that many animals do. It's a type of selection that gives offsprings a better chance to survive.

A 2019 Yale University study published in the journal PLOS ONE wanted to see how genes can affect a whether or not a couple stays together. Researchers studied nearly 200 married couples and surveyed them on their feelings about their relationship. Participants were then asked to provide a saliva sample to determine an individual's genetic make-up. When at least one partner had the GG genotype within the oxytocin gene receptor, the couple was more likely to report greater relationship satisfaction than those with other genotypes. This benefits the relationship as a whole since only one partner needs to have that genetic variation. So as researchers concluded, some people really are genetically predisposed to having long-lasting marriages. People with the GG genotype were also found to have a more secure attachment to their partners, which is the healthiest form of attachment you can have in a relationship.

"23andMe previously analyzed data based on more than 15,000 real-world couples who had children together and found that people paired with others who were more similar to them than they were different," Aaron Kleinman, PhD, senior computational biologist at 23andMe, tells Bustle. In their study, they found that athletes usually pair with other athletes, smokers go for other smokers, and vegetarians go for other vegetarians. So your genetics can influence your lifestyle habits, which will play a role in determining who you'll be compatible with.

Numerous studies have found links between lack of sleep and marital conflict. Couples who have fewer sleep problems tend to be happier overall. There are a number of different things that can make sleeping with a partner very challenging. If they have a tendency to move around a lot or accidentally kick you in their sleep, their genetics may be to blame. According to a 23andMe report, there is a specific gene marker that plays a role in sleep movement. The average person will move about 13 times an hour during sleep. But depending on someone's gene variants, they can move a lot more. If it's too much, it can disrupt your sleep, which can then affect how you feel in your relationship.

As of yet, scientists haven't really found a specific "cheater" gene. However, there are other things that can increase someone's likelihood of cheating. A 2010 Kinsey Insitute study published in the journal PLOS One found a link between dopamine receptors and infidelity. Dopamine is all about pleasure. It helps you feel attracted and excited about the person you're with. But as the study found, people who had some kind of deficiency in their dopamine receptors were more likely to engage in riskier behaviors like gambling or cheating. When someone has weaker dopamine receptors, they may need to seek out "bigger thrills" in order to feel pleasure. Because of that, it can make them more likely to sneak around and cheat.

A 2016 study published in the journal Human Nature found that your date's genes may have something to do with getting a second date. Researchers conducted a speed dating study of nearly 300 singles. After each "date," participants were asked to rate how desirable the other person was and if they were interested in going on a second date. Researchers also examined the DNA of each dater. As they found, men who had gene variants linked to leadership and social dominance and women who had gene variants linked to sensitivity were found to be more attractive. While social conditioning may have played a role in this, because these people had traits that were found to be more desirable, they were more likely to get asked out for a second date.

It's pretty fascinating how much of your life is influenced by your genes. These are just a few ways your DNA can affect your love life.