Romantic couples with a large age gap often raise eyebrows. Studies have found partners with more than a ten-year gap in age experience social disapproval. But when it comes to our own relationships, both men and women prefer someone their own age, but are open to someone 10-15 years their junior or senior.

While there is variation across cultures in the size of the difference in age-gap couples, all cultures demonstrate the age-gap couple phenomenon. In some non-Western countries, the average age gap is much larger than in Western countries. For example, in some African countries about 30% of unions reflect a large age gap.

So does age matter? And do couples with large age gaps experience poorer (or better) relationship outcomes compared to couples of similar ages?

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How many relationships have a big age gap?

Across Western countries, about 8% of all married heterosexual couples can be classified as having a large age gap (ten years or more). These generally involve older men partnered with younger women. About 1% of age-gap couples involve an older woman partnered with a younger man.

The limited evidence on same-sex couples, however, suggests the prevalence rates are higher. About 25% of male-male unions and 15% of female-female unions demonstrate a large age gap.

But what these trends tell us is that the majority of the population is likely to partner with someone of similar age. This largely has to do with having social circles that generally include peers of similar ages and being attracted to others who are similar. Similarity entails many things, including personality, interests and values, life goals and stage of life, and physical traits (age being a marker of physical appearance).

Why doesn’t age matter to some?

Many of the reasons proposed for age-gap couples have been largely rooted in evolutionary explanations, and focus on explaining older man-younger woman pairings.

From this perspective, it’s thought men’s preferences for younger women and women’s preferences for older men relate to reproductive fitness. That is, the extent to which someone has “good genes” – indicated by their attractiveness and sense of energy (also known as vitality) – and the extent to which they are a “good investment” – indicated by their status and resources as well as their warmth and sense of trust.

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Although men and women place importance on a partner who is warm and trustworthy, women place more importance on the status and resources of their male partner. This is largely because, with women being the child bearers, the investment is very high on their behalf (time and effort in child bearing and rearing). So they are attuned to looking for a partner who will also invest resources into a relationship and family.

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But because the building of resources takes time, we tend to acquire resources later in life and so are older by the time we have acquired enough wealth and resources to comfortably provide for others. So, women’s attunement to status and resources might explain why some women may be attracted to older men.

In contrast, there’s evidence to suggest men value attractiveness and vitality more than women because, from an evolutionary standpoint, youth is seen as an indicator of fertility. Given men cannot bear children, evolution suggests they’re attuned to younger women to enhance the chances of partnering with someone who can provide children.

But the evolutionary explanation is limited in that it doesn’t explain why the reverse occurs (an older woman-younger man pairing), or why age gaps exist within same-sex couples. For this, socio-cultural explanations might provide insights.

With more women working, in higher positions and being paid more, they no longer have such a reliance on men for resources. So fewer women will prioritise resources when looking for a mate.

As for same-sex couples, there’s very little research. Some suggest a lack of, or a reduced pool of, suitable age-similar mates may bring about same-sex coupling with large age differences.

What are the relationship outcomes for age-gap couples?

Many people assume that age-gap couples fare poorly when it comes to relationship outcomes. But some studies find the relationship satisfaction reported by age-gap couples is higher. These couples also seem to report greater trust and commitment and lower jealousy than similar-age couples. Over three-quarters of couples where younger women are partnered with older men report satisfying romantic relationships.

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A factor that does impact on the relationship outcomes of age-gap couples is their perceptions of social disapproval. That is, if people in age-gap couples believe their family, friends and wider community disapprove of their union, then relationship commitment decreases and the risk of break-up increases.

These effects appear to apply to heterosexual and same-sex couples. So the negative outcomes for age-gap couples seem to reside not in problems within the couple, but in pressures and judgments from the outside world.

Another factor at play may have to do with the stage of life each partner is experiencing. For instance, a ten-year gap between a 20-year-old and a 30-year-old may bring up different challenges and issues than for a ten-year gap where one partner is 53 and the other is 63.

This is because our lives are made up of different stages, and each stage consists of particular life tasks we need to master. And we give priority to the mastery of different tasks during these distinct stages of our lives. So when each member of a couple straddles a different life stage, it may be difficult for the couple to reconcile each other’s differing life needs and goals.

Does age matter?

The success of a relationship depends on the extent to which partners share similar values, beliefs and goals about their relationship; support each other in achieving personal goals; foster relationship commitment, trust and intimacy; and resolve problems in constructive ways. These factors have little do with age.

So the reality is, while an age gap may bring about some challenges for couples, so long as couples work at their relationship, age should be no barrier.