What makes it easy or hard for someone to form close relationships? Is it how they were raised or the genes they inherited? For years, two major theories have tried to answer this question. One suggests that a warm, supportive upbringing helps people build strong bonds as adults. The other argues that genetics—specifically, genes affecting brain chemicals that control anxiety—shape how well people connect with others.
Either way, parents seem to take the blame. They’re either faulted for being cold and distant or for passing down genes linked to anxiety and other traits that make bonding difficult.
Scientific studies have shown that brain chemicals like dopamine, oxytocin, serotonin, and opioids influence mood, anxiety, and caregiving behaviors. Some genetic variations related to these chemicals have been linked to success in forming close relationships. Research on identical twins, who share all their genes, supports the idea that genetics plays a role. One gene in particular—HTR2A, related to serotonin—has been tied to how anxious people feel in relationships.
However, a long-term study published in the May 2013 issue of Journal of Personality and Social Psychology offers new insights. Researchers tracked individuals from birth to age 18 and then studied their adult relationships.
They found that while early life experiences—like having a sensitive mother or growing up without a father—were linked to adult attachment styles, the connections were weak. The same was true for genetics. The only gene that showed a slight effect was the serotonin gene variant rs6313. People with this variant reported more anxiety in relationships. But overall, the researchers concluded that neither childhood temperament nor genetics explained much about adult attachment styles. In fact, they estimated that genes account for only about 1% of the variation in how adults form relationships.
The key takeaway: both childhood experience and genetics matter a little—but not a lot. That makes it hard to place blame solely on parenting or biology.
Instead, the study suggests that adult relationship patterns are shaped more by current experiences than by the distant past. People tend to feel more secure in relationships when their emotional needs are met in the present. Insecurity rises when those needs go unmet. Forming close bonds is a complex process influenced by many factors, not just early life or one gene.
This research doesn’t dismiss the role of childhood or genetics. Instead, it views them as the base of a much larger structure, built over time through many life experiences.
And while this study focused only on adult attachment, there are many other childhood and teen behaviors influenced by both genes and environment. It also didn’t explore one other common theory about relationship struggles: blaming your partner.
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