Next Time Your Mom Asks Why You're Not Married, Show Her This

Next time your mother bugs you about being single, blame her.

According to recent research at Peking University in Beijing published last week in the journal Nature, some people have a gene that makes them bad at relationships. And that gene has nothing to do with appearance or personality.

Rather, the research team found that some people have a gene that results in lower levels of serotonin, which causes lower levels of comfort in a close relationship. An affinity toward relationship behaviors, "such as pair bonding and affective affiliation," have been found to be tied to the brain's levels of serotonin.

The science: Researchers surveyed roughly 600 Chinese undergraduate students, asking questions about their relationship status before collecting hair samples to be genotyped.

In their testing, the researchers focused on a gene called 5-HTA1, which affects serotonin levels. Upon further investigation of the gene, they discovered that there was a "considerable difference" between how many people were single who had the "C" allele of the gene (about 50%) versus another "G" allele (about 60%). In other words, some people are just genetically less able to develop feelings of a close relationship.

It's not just biology: The high number of single students isn't just about genetics – it's also about societal norms. Findings from earlier this year found that roughly half of adults aged 16 and older were single. When the same survey was taken back in 1976, the percentage was 37.4%.

Moreover, the undergraduates surveyed by the researchers likely weren't old enough for relationships to be a top priority. In America particularly, people are marrying later and later in life. A Pew study revealed that only 26% of Americans ages 18 to 32 are married, which is significantly less in comparison to older generations.

So while biological factors may come into play, they're likely just being exacerbated by very apparent and, in certain ways, uniquely millennial societal factors.

But for those with the "G" allele, no need to fret – there are plenty of single people right there with you, and there's no reason why your genetics have to determine everything about you. Just think of it as a great excuse to wave off millennials' dating habits to the older generations.