How your birth order affects your romantic compatibility
Find out which marriage combinations work best - and how yours compares - in this extract from Dr Kevin Leman's book, The Birth Order Connection. This advice applies to all other intimate relationships too.
Best birth order marriages
Only child and youngest; first-born and youngest; middle child and youngest: Gender plays a role here as well. If you want the absolute best match, it's female only or first-born marrying a male youngest child who has older sisters.
The last born with older sisters is going to be the sort of person who brings out the maternal instinct in women, and the oldest sister is likely to have great maternal urges. He would have grown up with girls who have doted on him. This is similar to the treatment he seeks in a wife, and the best place he'll find it is with an oldest sister. The match works both ways.
The first-born needs someone to show her pleasures of sunsets, rainbows, and to remind her that it can be fun to let her mind wander and do something mad or different. The last-born needs someone to show him that while having fun is a wonderful thing, it takes hard work and perseverance to make those daydreams into reality.
First-born married to a first-born: This relationship is likely to be high friction - either butting heads from day one, or falling into a controller-pleaser pattern. It can be difficult to make this pairing work.
First-born married to a middle child: The danger here is that the middle-born may alter his or her own behaviour to please the first-born. While the middle one makes a good match for anyone (except, perhaps, for another middle), she may find the first-born to be somewhat intimidating and thus will need drawing out.
If you marry a hard-driving first-born, you may be inclined to give up your own desires and dreams to please your more dominant, first-born spouse. However, if you have last-born tendencies, this can be a very good match for you.
First-born married to the last-born: This relationship is an excellent combination. First-born can teach last-born how to be better organised and that there are times when life must be taken seriously. The last-born teaches the first-born that it's okay to have fun once in a while.
What are the worst combinations?
Middle child married to a middle child: This relationship has the potential to go either way. If one of the middle-borns has first-born tendencies and one has last-born tendencies and traits, this can be a good match.
On the other hand, if both partners share the solid and secretive characteristics of middle borns, communication is likely to suffer - though you'll do well compromising to get along and keep the peace. This match has the least chance of experiencing marital infidelity.
Middle child married to last born: Works best if the middle born has some first-born tendencies. If the middle is a true middle, she may find himself pulled into the last-born's more irresponsible lifestyle, creating the problems seen in a last-born to last-born marriage. If she has last-born tendencies, there could be trouble. If she has first-born traits, then a great match.
Last born married to a last born: Be careful here. You may have fun, but you'll also feel like life is getting a little out of control, with nobody in charge. Even last-borns can handle controlled chaos for only so long.
Worst birth order mix
Only-child female and an only-child male: Not only will the two butt heads, but neither will have much of a clue about the other gender.
Female last-born with no brothers and male last-born with no sisters: Not only are you compounding the problems of two last-borns, but neither really knows very much about the opposite sex - at least in a psychological sense - and so wouldn't be particularly understanding and supportive of each other.
From The Birth Order Connection