Does your birth order determine the success of your marriage?

Bride putting ring on groom's finger. Rings exchange. Happy couple celebrating wedding outdoors in summer.
It is thought that birth order may influence personality, which could in turn influence romantic success. (Getty Images)

It’s been said that the order in which you are born can influence your personality type. But did you know it could also influence how successful your marriage is?

At least, some studies have suggested that this may be the case. Toni Tone, author of the best-selling I Wish I Knew This Earlier: Lessons on Love, recently shared a TikTok video exploring the evidence and sparked plenty of conversation on the topic.

In Tone’s video, which has been viewed more than three million times at the time of writing, she referred to studies that looked into how birth order impacts marital success, including one that suggests that "individuals with different birth orders are actually generally more successful than unions of individuals with the same birth order".

This means that a marriage between someone who was born the eldest child in their family and someone who was born the youngest may have a better chance of longevity, compared to two first-born children or even two people who were the only child in their family.

The possibility that birth order has a significant influence on romantic compatibility has been explored for some time. In the late Fifties, Austrian psychologist Walter Toman first proposed that some couplings will be more harmonious depending on the birth order of each party compared to others.

There have been some studies in more recent years examining this theory. Psychologist Kevin Leman, who Tone referred to in her TikTok video, outlined distinct traits that are associated with first-borns, middle-borns and last-borns, and these particular traits can make or break a marriage.

Leman posited that first-born children tend to 'rule', while middle-born children 'mediate' and last-born children 'charm'. Tone explained: "For that reason, you tend to see a higher divorce rate in people who are both first-borns because they potentially butt heads."

Being an only child may also affect marital success. According to Tone, the only divorce rate that is higher than first-borns who marry other first-borns is an only child who marries another only child.

This is backed by some studies that suggest having siblings may reduce a person’s risk of going through a divorce. A 2016 study by researchers at the Ohio State University found that, with each additional sibling, a person’s likelihood of divorce declines by 3%.

But the topic remains highly debated, says relationship psychologist Dr Limor Gottlieb, who tells Yahoo UK that there is no clear agreement about whether birth order really has such significant impacts on a person’s life.

"Only few studies investigated the bird order effect in relationship outcomes and the results are mixed," she says. "However, there are some personality studies that show general trends of birth order that could have something to do with relationship success.

"The firstborn child tends to be more responsible and conventional and is more inclined to please their parents - the personality trait associated with firstborns is agreeableness. According to relationship research, agreeableness is an important trait in relationship maintenance.

"In contrast, second born children tend to be more rebellious, and the personality trait associated is open to experience. From an evolutionary perspective it could be that because the first child took the role of the responsible one, the second child can be free to explore which can come across as rebellious behaviour even when it’s not."

Dr Gottlieb adds: "This could mean that second born children don’t conform to societal norms of getting married or being monogamous. Indeed being open to experience has also been associated with infidelity."

When it comes to people who were born last in their family, these individuals tend to be more social and identify less with their parents, as they are not competing for their parents’ attention.

"But similarly to firstborns they also tend to score high on the personality trait of agreeableness, as well as extraversion," Dr Gottlieb says. "These children tend to be very charming and successful with their peers which would make it easier for them to find relationship partners and their people skills can make them successful in personal relationships."

Lots of other factors affect a relationship and its potential success or failure. (Getty Images)
Lots of other factors affect a relationship and its potential success or failure. (Getty Images)

Are people who were born as the only child doomed if they marry another only child? Studies might suggest that, but Dr Gottlieb says that these individuals may have more tools to be resilient and make successful life choices - including finding the right partner for marriage.

"In one child families there are no siblings to compete with for parental attention," she explains. "Therefore they tend to be closer to their parents but are also free to explore their personality without confounding factors.

"The close-knit relationship with their parents gives them the necessary interactions to promote better development and these children tend to be more motivated and better adjusted compared to children with siblings."

However, Dr Gottlieb suggests taking these findings with "a grain of salt" and to remember that a number of other factors are at play in relationships.

Whether you are a first-born married to a last-born, or a middle-born married to an only child, what matters is putting your partner first, as well as respecting one another and valuing your relationship.

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