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.

According to psychologist Kevin Leman in his book "The New Birth Order Book: Why You are the Way You are," birth order can influence the health of a partnership. Leman references a study published in the Journal of Marriage and Family that evaluated the relationship quality of 236 business executives and their partners based on birth order combinations. 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. Remember, this is only a general guide and not all marriages and individuals will follow this pattern.

If you are a firstborn...

Best match: Lastborn

Worst match: Another firstborn

According to a study by Walter Toman, a professor of Clinical Psychology at the University of Erlangen-Nuremberg in Germany, on 3,000 families, you have pretty good odds of a successful marriage if you're a firstborn who marries a lastborn. Leman says that is because there's an opposites-attract thing going on.

The firstborn is more Type A, and teaches the lastborn little things about organisation, whereas the lastborn helps keep the atmosphere light and reminds the firstborn not to take everything so seriously.

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. They tend to bump heads because firstborns can be perfectionists and like having things done their own way, so it's all a matter of control.

That doesn't mean you're doomed from the start, though. For example, Hillary and Bill Clinton, who have been married 41 years, are both firstborns.

To learn to let go, Leman writes that you should stop trying to improve your spouse, and instead bite your tongue and stop criticising. He also says that you should define your roles carefully, so there's no power play over who pays the bills or who does the shopping.

Firstborn-middle child relationships can be confusing for firstborns, because middle children can be closed off and bad at communicating their feelings. 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."

Hillary and Bill Clinton are a famous firstborn couple. (REUTERS/Ana Martinez)

If you are a middle child...

Best match: lastborn

Worst match: Another middle child

As the rule goes, Leman says, middle children do not communicate well, and this is twice as bad in a middle child partnership. 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. However, this can be confusing to their partners because middle children can often hide their emotions instead of talking about what they really feel.

To ease the tension, Leman says that a suggestion bowl can work well. Or, to keep things simple, just find little ways of building up each others' self-esteem by doing special things for each other. It's also important to make sure to give each other plenty of space for outside friendships and to show each other a lot of mutual respect, like phoning to say if you're running late.

Middle child-lastborn couples are a pretty good match. Leman says that a compromising middle child tends to make a good partner for lastborns who are usually socially outgoing. They also have good communication, because middle children are not threatened by lastborns, so their communication problems aren't so much of an issue.

There is a risk of middleborns being condescending, so Leman says to be wary of that. Also, it is important to realise that lastborns have a selfish streak and can be demanding. The general rule, Leman says, is to not make fun at your spouse's expense; always laugh with your mate not at him or her.

(Getty Images/iStockphoto (Getty Images/iStockphoto)

If you are a lastborn...

Best match: firstborn

Worst match: Another lastborn

Two lastborns in a relationship is chaos. Lastborns have a tendency to get into financial trouble in a marriage, and it takes a lot of extra effort in this kind of relationship to work through who pays bills, who cleans up, who takes care of the social calendar, etc. If no firm decisions are made, lastborn pairs can quickly get into a lot of trouble.

According to Leman, lastborns have a built-in tendency to pass the buck. 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. You should also hold each other accountable for things and avoid being defensive. Most importantly, keep your sense of humour and try to stay laid back, which are lastborns' natural qualities anyway.

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