The Power & Influence of Birth Order

Check out my latest blog post over at here or after the jump.


Did you feel like you grew up in the shadow of a larger-than-life big brother or big sister?

Were you an only child who struggled with sharing a dorm room?

Or the firstborn who could do no wrong, and then got to college and went hog-wild with pent-up rebellion?

For as long as I can remember, I’ve been absolutely and utterly fascinated by birth order: how it explains so much about who we are, and why we gravitate towards certain friends/mates.

As this article about the power of birth order observes, “Of all the things that shape who we are, few seem more arbitrary than the sequence in which we and our siblings pop out of the womb. Maybe it’s your genes that make you a gifted athlete, your training that makes you an accomplished actress, an accident of brain chemistry that makes you a drunk instead of a President. But in family after family, case study after case study, the simple roll of the birth-date dice has an odd and arbitrary power all its own.”

Of course, not everyone fits perfectly into the stereotypical mold of their birth order ranking – key variables such as gender, our upbringing and environment play a huge role in how we develop – but knowing the basics of birth order with respect to personality can often help us understand why we are the way we are.

In my family, the two-year age gap between each child coupled with the order of girl-boy-girl meant there was very little competition or rivalry between us; sure, we fought like any siblings do, but we were always close – and today, my siblings are two of my best friends. And the three of us fit the birth order models to a “T.”

For example, I’m your “typical firstborn”: Type-A, perfectionist, very hard on myself, a little too rigid at times, a bit stubborn, and very much a people-pleaser.

My brother, two years younger than me but the only son, exhibits a lot of firstborn male traits (including being super-protective of his sisters, like a “big brother”) … but he is much less uptight than me and more artsy/exploratory than me. Sandwiched between two head-strong females, he is certainly not the typical middle child vying for his place in the family, but rather the great equalizer among us (this is an example where the girl-boy-girl order has influence).

And my sister, four years younger than me, is your stereotypical baby. Sociable and outgoing, she worked hard to carve out her own niche, to differentiate herself from my brother and I – and she’s done an amazing job at creating her own identity.

Naturally, of the three of us, I’m the one who ended up with anxiety issues, etc. – which didn’t surprise my therapist in the slightest as soon as she found out I was a firstborn.

With this in mind, I got to thinking about my own friends – from middle school/high school in particular – and one thing stood out: all of my high school friends were firstborns (except for one who was, like my husband–the second in his family, but the first male). We were all over-achievers, and, not surprisingly, today, each of them is successful in their own right … and we’re still very close friends.

And though my brother has a mixed bag when it comes to his childhood friends, nearly all of my sister’s childhood friends are, like her, the babies in their families … which, naturally, got me thinking that perhaps there was something to be said for birth order and friendships, dating as far back as the playground days.

Over the years, I’ve read lots about birth order and mates (which I’ll get to later) but I was curious about our early friendships and birth order, as those early years are when our personalities really start to take shape.

So, since I sure as heck don’t have time or resources to conduct focus groups or a real survey, I decided to do the next best thing I could think of: an informal poll on Facebook. I wanted to see what I could discover anecdotally, and while I hoped my (unscientific) sample would prove my little hypothesis, I knew nothing was certain.

The results of the 20 respondents were surprising and staggering. The majority of my friends who responded were the oldest in their family (13). Six were babies, one was a middle child and one was an only child.

Of the 13 firstborns, nearly half (six) were mostly (childhood) friends with other firstborns. There was a mix with the rest. And of the six babies, four were friends with middles or a mix, one had mostly baby/only friends, and one had oldest/only friends. The raw data is below.

Rank—Friends’ Rank (mate, if info was shared)
Oldest—all over
Oldest—oldest/all over
Oldest—oldest/only (married to middle)
Oldest—oldest (married to baby)
Oldest—middle/baby (married to baby)
Oldest—oldest/middle (dating middle)
Oldest—mix (married to oldest)
Oldest—mix, few firstborns
Middle—“all over the place”
Baby—middle kids
Baby—mix, baby/middle

I knew it was a random sample and not scientific at all, but I was hoping to see some concrete evidence that, in our youth, we befriend similarly-ranked birth order friends. And in some cases this was true (particularly for half the firstborns), but certainly not in all cases.

Though I was a little disappointed that my hypothesis wasn’t proven, I didn’t give up. Next, I did an unofficial Facebook survey on birth order and our choice in mates. The results there were much more of what I expected to see, based on my knowledge of birth order and its influence on mates.

For example, stereotypically, firstborns and babies are considered the perfect birth order match (they tend to balance one another out)… and, not surprisingly, nearly half my respondents fell into that camp.

(Specifically, firstborn male/baby female is the ideal coupling, but I didn’t take sex into account in this very unscientific poll).

Of 31 responses, there were 14 oldest-baby combos; five oldest-middle combos; five oldest-oldest combos; two oldest-only combos; one middle-middle combo; one middle-baby combo; one baby-baby combo; one middle-only combo; one only-oldest.

Rank—Mates’ Rank


So looking at my “data” it was pretty obvious to me that when it comes to finding a mate, many people are drawn to their opposite; the whole “opposites-attract” notion.

Of course, there are no guarantees for what will make a relationship work (and some pairings that birth order theory wouldn’t expect to work — i.e., oldest-oldest; baby-baby — do), but knowing where each other stands in the context of his/her family’s birth order can be a great way to understand why they are the way they are, and can help improve relationships, too.

To learn more about birth order, check out this book, The Birth Order Book: Why You Are the Way You Are, by Dr. Kevin Leman (available on

How about you? Where do you fall in your family’s birth order? Where does your mate or best friend fall in birth order? How do you think your place in your family’s birth order influenced you in terms of self esteem/confidence? And if you have children, do you see their personalities influenced by their position in your family?


5 thoughts on “The Power & Influence of Birth Order

  1. My brother is 18 months older than me, and I think we have more “gender” differences than birth order differences. B/c we were only a year a part in school, there weren’t a lot of older/younger roles that were defined. There were more that, my brother had to help my dad more with the farm work (my dad is a rancher) than I did, but if it was something that we both could do, than I was out helping too. Personality wise, I’m probably a little more “bubbly” than my brother, but again, I think that’s partially due to that I’m a girl, and more social, but my brother does like to have his share of talking.
    My mom is the oldest of 4 in her family, and my dad is the youngest of 3, and I can see the birth order differences in that. My mom is more organized, very to the point, where as my dad is pretty social, easy going.

  2. Lori, I think for a lot of people, gender plays a big role. And your parents have what appears to be a great match. I can totally see it in my own parents, too (my mom’s the baby, my dad is the firstborn).

  3. Finally reading this post!
    I have that book by Leman and enjoyed it very much. I have always been interested in birth order theory, my dad being one of 8 children, my mom one of 4, and myself one of 5!
    My situation is always a hard case study, because there are large age gaps between me and some of my siblings, as well as some half-sibling action, thus having influence from step-parents, etc.
    I am my mom’s third child, but my dad’s first. Therefore I have many first-born qualities (8 years between me and my older sister), but also some middle-child qualities, since my little brother came along a couple years after me.
    It is all so interesting and reading your post is making me want to read that book again and analyze my husband! 😉

  4. I’m the firstborn of two children (youngest a male) and I’m interested in finding out the effects of birth order on friendship.
    I’ve had some really bad experiences with lastborns from large families. They tend to leave all contact and initiation to others, and for reasons beyond my understanding, it never dawns on them to ever call anyone and see how they’re doing. hey only call to return calls or possibly to issue an invitation. Other than that, zip, zero, nada. What’s wrong with these people?!

    I think folks from large families truly don’t feel they need to be real friends with anyone outside of their siblings, so they can take you or leave you. Doesn’t matter to them either way.

    Anyone else notice this?

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