A study published last week in Scientific Reports investigated how the expression of a gene correlates with relationship status. The gene in question is not 5-HTA1 — as others have reported — but, rather, 5-HT1A. The gene is named for the specific type of serotonin receptors it encodes. The 579 research participants were all unrelated, Chinese adults that had an average age of 24. For the study, they each donated a hair sample and were asked to state whether or not they were currently in love.
The results showed that relationship status — single or in a relationship — was significantly associated with having the C or G allele of the 5-HT1A gene. Over 60% of those with both G alleles (GG genotype) and those with only one G alleles (CG genotype) were more likely to be single. The findings were more evenly split for those with both C alleles (CC genotype): Only 49.6% were single. So, those with a G allele were slightly more likely to be single than those with the CC genotype.
It seems like a stretch to blame your romantic life (or lack thereof) on a single allele of a single gene, but previous research has been able to connect a lot of life factors to 5-HT1A expression, such as the likelihood of developing mental health issues. That said, the opposite has also been found: Having fewer serotonin receptors has been linked to panic disorder and depression. This suggests there's something going on here that isn't being captured by these correlation studies. And, it's probably a combination of elements that are futzing with your relationships — not just your genes.
Luckily, while your genetic makeup might play a role in determining your behavior, it certainly isn't your destiny — romantic or otherwise.