In theory, birth order can have either a positive or negative effect on the romantic compatibility of couples. A common belief is that marriages and intimate relationships are less risky if the involved pair does not share the same birth position. However, the idea that romantic relationships are doomed because the birth order theory dictates this outcome is a bit of a misconception. Intimacy can bring out characteristics that allow two people within the same birth position to complement each other rather than clash. While Alfred Adler’s birth order theory emphasizes general personality traits, a determining factor for the development of those traits rests with the individual’s interpretation. To help explain, here is a real life example:

*Carly, a firstborn, married an only child and from the very beginning they constantly argued. Their fighting was notorious for ruining family holiday gatherings, family dinners and even children’s birthday parties. Both had control issues and lacked conflict resolution skills. Those strong personality traits overshadowed everything else in their relationship, and the results were disastrous.

However, after Carly moved on from her first marriage, she soon married a firstborn. Even though the various combinations of firstborns and only children can be the most volatile romantic match up, the two like-minded birth order personalities get along. With her new husband, Carly works harder to compromise, therefore lessening her need for control. Why the big change? Keeping with the birth order premise, it could be the less discussed part of Alfred Adler’s theory for personality influences. Commonly observed are the external influences – siblings, parents and environment. However, the other part of his theory deals with the internals – role interpretation and acceptance.

For Carly, the special attention and authority she received in her position as the oldest was completely embraced. In contrast, the expectations and responsibilities thrust upon her as the firstborn were totally rejected. She was deeply conflicted about her role in the family. To her, it was both a blessing and a curse. Her dual interpretation or response to her birth position created dual reactions – one for each partner.

With her first husband, (the only child), Carly had a difficult relationship. In addition to the common birth order traits that caused them to clash, there was an “every man for himself” undercurrent running throughout their relationship. Carly struggled for relevance and control which was her familiar understanding of her birth right.

On the other hand, Carly’s experience with her second husband is positive. Why? Because as a firstborn he was used having authority, but he was also used to looking after his younger sibling. His protective disposition is prominent in the marriage. Carly stopped wrestling for control, therefore relieving her of the pressures and responsibilities she felt burdened with as a firstborn. Happily, the “curse”, the other interpretation of her birth order, is finally gone.

For Carly there were two different husbands, two different interpretations, two different outcomes – same birth order premise.


While it’s possible and even probable that birth order can significantly impact romantic matchups, there aren’t any set rules. So, what should you look for in a significant other? Search for someone who naturally balances you. They should be similar enough to share your goals, aspirations and direction in life. Yet, still different enough to strengthen your weaknesses and value your strengths. Compatibility should be the main goal - no matter what the order of birth.


Compatible Birth Order Positions (Remember there are no set rules!)

Worst Matches

Firstborn + Firstborn
Firstborn + Only Child
Only Child + Only Child

Bad (or not so good) Matches

Middle Child + Middle Child
Last Born + Last Born

Better Matches

Firstborn + Middle Child
Middle Child + Last Born

Best Match

Firstborn + Last Born


*name change