OK, but since fraternal twins are as similar as any other set of siblings, I don't think the answer for them is interesting.

My DH is a fraternal twin. He and his brother couldn't be more different. Same for our own 20-year old twin daughters.

Since for fraternal or dizygotic twins, two eggs (ova) are fertilized by two sperm and produce two genetically unique children, they are like any other sibling, other than sharing similar milestones.

Anonymous wrote:I think twins or multiples -who are identical- from the same egg -- are what's being asked!

Nothing in the OP indicated that.

My mom and her identical twin (in their 70s now) are still very similar, personality-wise, although their life trajectories have been a bit different. They're closer to each other than their other siblings.

I think twins or multiples -who are identical- from the same egg -- are what's being asked!

Anonymous wrote:If you've a set of grown twins or multiples, are they similar in nature or different?

B/G twins, almost 20. B is fairly quiet and can struggle socially. G is fairly extroverted and super strong student. Competition occasionally an issue, but perhaps less so now as they are at different colleges. Both are kind and compassionate as well as aware of their privileged upbringing.

Anonymous wrote:I have a set of triplets that includes a pair of identicals. The identicals are FAR more similar. Like no comparison. The fraternal is no more similar than another sibling.

Wow!

I have 20.5 year old fraternal b/g twins. They are VERY different which is understandable, they are just brother and sister who happened to be born at the same time. My DS is very shy and introverted, super hard worker, high high GPA, very mature beyond his years. My DD is an extravert, loves being around people, the busier the better.

They happen to go to the same college - not by design but because it was their favorite. If they hadn't both gotten in, they'd be at separate schools. They only see each other maybe 1-2 times per week. Other than bickering about sharing the car, they get along great but are not involved in each others daily lives.

I have a set of triplets that includes a pair of identicals. The identicals are FAR more similar. Like no comparison. The fraternal is no more similar than another sibling.

Obviously there are studies but personal stories are interesting.

My friends have twins and triplets, everyone seems unique though there are some similarities due to growing up together with same parents, surrounding, schools and colleges. I wonder if identical twins are more alike in nature than ones who aren't.

Anonymous wrote:My 20 year old twins are fraternal. One is an introvert. The other is an extreme extrovert. They have always adored each other.

Girls or boys?

My 20 year old twins are fraternal. One is an introvert. The other is an extreme extrovert. They have always adored each other.

If you've a set of grown twins or multiples, are they similar in nature or different?