According to the study, the best possible match is a firstborn female with a lastborn male, because their needs are in harmony with each other.
A firstborn with another firstborn, Leman writes, is likely to be a power struggle.
Remember, this is only a general guide and not all marriages and individuals will follow this pattern.
Leman says that these couples should learn to open up to each other more, and firstborns should encourage middle children to speak by asking things like: "What do you think?
" "Tell me how you really feel," or "Tell me more." As the rule goes, Leman says, middle children do not communicate well, and this is twice as bad in a middle child partnership.
Finding the right partner can be challenging at the best of times.
To make things more complicated, psychologists believe that we might be more suited to each other depending on the order in which we were born.
They don't tend to confront each other about things, because they feel it isn't worth the hassle, and instead bottle up their emotions.
Middle children supposedly have the best track record for building a lasting marriage, because they grow up learning to compromise and negotiate with their siblings, according to Leman.
So if both partners are hellbent on blaming each other for everything, that's not going to end well.
To help ensure this doesn't happen, Leman suggests being wary of selective listening, and to make sure you're not manipulating each other.
The distinct traits associated with different birth orders, some of which are outlined in 2003 study in Human Nature, can serve as a gauge for whether or not two people will make a good match.
Using Leman's book and the previous studies, we've identified the best (and worst) mates based on birth order.
You should also hold each other accountable for things and avoid being defensive.