The Three Secrets You Will Never Guess About Differences Between Siblings

How can siblings be so different? My sister and I are different on many levels; from our personalities to physical appearance, sometimes it’s hard to believe we are related. My brother and I are just as dissimilar when it comes to how we look and act! My daughters have been unique and unalike since birth (and the exact same age difference as me and my sister). Even when siblings share genes, they can have opposite physical and personality characteristics. Today I’m sharing The Three Secrets You Will Never Guess About Differences Between Siblings.

Why Are Siblings Different?

The difference between siblings start with genetics. In an effort to understand how two sisters can be so different, I have read countless studies on siblings. A parents’ genes play a huge role in the making of a child. Mom passes 23 chromosomes along and Dad passes 23 chromosomes along, resulting in a baby with 46 chromosomes. On average, children with the same biological parents share about 50 percent of their genes with each of their brothers and sisters. The key regarding genetic distribution is the combination of genes inherited by each child.

Let’s look at me and my husband as toddlers, as well as Annabelle and Ailey at the same age:

It’s obvious they inherited a mixture of physical features from their Mom and Dad, but no more one than the other. As the girls get older, they change too! Sometimes we hear Ailey looks like me now, while other times people say Annabelle looks more like Mom. Physical differences between siblings are so common and seem to be more understandable than personality differences.

Personality Differences Between Siblings

I find my extraordinary daughters fascinating with their impressionable and unique personalities. It’s hard to believe in just a few months we are going to have another daughter! Brandon and I wonder often if she will be more like Annabelle or Ailey, or possibly a whole new little Houston.

Read: How to Prepare Your Child For a Sibling

“Personality characteristics are rarely due to a single gene. There’s not a gene for conscientiousness, leadership ability, criminality, or any other psychological characteristic. These complex patterns of behavior are affected by particular combinations of genes acting on the development of the brain and other parts of the nervous system. One sibling could have several genes that, together, predispose him or her to have a certain characteristic, but a sibling who shared half of those genes wouldn’t show any of that same characteristic at all. Having half the genes for that trait might not result in that trait.” (source)

I would like to publicly apologize to our Annabelle for saying she was a handful as a toddler. I didn’t know what that meant until Ailey strutted into our world. We always heard the second child could be the complete opposite of your first, but a parent cannot anticipate the differences until they’re in the middle of it all.

How are your children different?

There are so many fascinating theories as to why siblings have different personalities despite sharing the same parents and living environment. From Darwin’s principle of divergence to non-shared environment theory, siblings personalities can be vastly unalike.

Annabelle was curious, inquisitive, cautious, delicate, and slow paced. Ailey… Ailey is just as curious, but on a whole other level. She doesn’t want to just know what something is, she wants to see how it works for herself. She is determined, reckless, fearless, and feisty. Ailey has her sister’s temper times two and her level of venture is immeasurable.

As the girls get older, new personality traits develop. While Ailey is very empathetic, Annabelle is tough to forgive and admit her wrongdoings. She must get that from her Dad. They both share a fantastic sense of humor and wild imagination though!

Parents Can Influence Differences Between Siblings

Without realizing it, parents and other family members can influence differences between siblings. Even minor personality differences can become exaggerated within families. For example, Annabelle is more delicate when it comes to injuries while Ailey has a higher tolerance for pain – so we definitely will coddle one over the other. Our third daughter may be given extra special attention by her two older sisters even if she is tough from the start.

Let’s Not Forget the Birth Order Stereotypes

Studies show that birth order affects personality – especially with society encouraging this theory. As we prepare for our third to arrive, people are already commenting on how Ailey will change as she enters the ‘middle child’ role. There are both positive and negative connotations surrounding the characteristics of a child based on birth order. We all know some are unavoidable – like the youngest being the baby of the family. There is also the notion that the youngest child will be attention seeking whilst in the shadow of his or her elder sibling(s).

Ailey definitely seeks our attention more often than Annabelle, even though she has always been my little shadow. I do worry a little bit how she will handle a new sibling in the house… but she is going to love being a big sister and having someone to care for.

Overall, I find it so fascinating to watch our daughters grow and change. It’s interesting to see a little bit of myself in the girls, a bit of their Dad, and then a special combination of both our personalities. How are you different than your siblings?