The #1 Resource & Support Network for Parents of Twins

The #1 Resource & Support Network for Parents of Twins

Are Twins Hereditary?

Are Twins Hereditary?

are twins hereditary

Last updated on July 12th, 2024 at 01:13 pm

Yes, twins can run in families, but it depends on the type of twins. There are two primary types: fraternal (dizygotic) and identical (monozygotic). Fraternal twins are like having two siblings who happen to be born on the same day, each with their own unique traits and personalities, akin to getting a mixed bag of surprises. On the other hand, identical twins are like having a clone who shares your birthday, where one original blueprint splits into two identical copies, creating a double dose of the same genetic flavor.

Fraternal Twins (Dizygotic):

  • Fraternal twins happen when two separate eggs are fertilized by two separate sperm. It’s like when you go to the bakery and they give you an extra donut just because they’re feeling generous.
  • This type of twinning tends to run in families. If your grandma, mom, or sister has a history of producing double yolks, you might just end up with two buns in the oven yourself.
  • It’s passed through the maternal line, so ladies, if twinning runs in your family, you might want to start preparing for double trouble!

Identical Twins (Monozygotic):

  • Identical twins result from a single fertilized egg splitting into two embryos. This type of twinning does not appear to be influenced by genetics and is generally considered a random event.
  • There is no clear evidence that identical twins run in families or are influenced by hereditary factors.

Other factors can up your odds of having twins too: being over 30 (because mature eggs apparently like to party in pairs), fertility treatments (science playing matchmaker), and certain ethnic backgrounds (some cultures just have a knack for doubling down).

So, whether it’s the family tree or just a cosmic roll of the dice, twins can make life twice as nice—or at least twice as interesting!

Hereditary Twins
PC: Mary Greenwood

We Asked Our Community if Twins Run in Their Families…

This is what they had to say:

My grandmothers sister had twins in 1930 and we shared the same name. My grandma always told me growing up that I’d have twins and she was right! I’m the only other person in our family to have them.

Yes, and usually in opposite directions 😳🙄

We have identical boys, and identical twins are supposedly random, although there are incidences of families having fraternal and identical.… 

No. HUGE shock for us. We never ever thought we’d have twins. We have ID

“Now they do” – my standard answer to strangers who I didn’t want to start a discussion of my reproductive history with.

Yes. Also, my twins were born on my mother and her twins’ birthday 🙃

Yes. Fraternal on both sides. My side it’s hit every generation at least once going back to my great great grandparents

Very much so, as do triplets. I was lucky to get 2.

Yes. On both of my sides. I was a twin. But, my girls are ivf twins.

Randomly on my mother’s side. I was one of like 4 or 5 people on her side that had twins.

My husband is a twin but twins to not run on either side. His parents conceived with fertility meds and so did we.

twin pregnancy timeline week by week

If you just heard that second heartbeat for the first time, or you know it’s been two for a while, you need to read our twin pregnancy week by week timeline to help you learn what happens week by week with twins. Click here to learn more… and while you’re at it, check out our expecting twins classes and twin parent coaching services.

Yes. My fraternal twins are the 9th set of twins just on my side of the family. My husbands side has an identical set but I know that’s not genetic lol

No, my maternal grandpa was a historian and could only find one set which were distant cousins from almost 100 years ago. Coincidentally though, my moms sister had the exact same set as me (identical girls) a few years after i did. How weird right?

Maybe: my grandfather had twin sisters. If it were my grandmother, it would have been a hands-down yes, but because it was my grandfather it seems to stump everyone. Can men pass a twin gene to their daughters?

Yes there are 9 sets of them.

13 sets of twins between my husband and i’s families. My identical girls were born in February, a cousin’s identical girls were born in March and my sister’s identical girls are due in November. But identical aren’t genetic we were told 🤔

My mother was a fraternal twin, my husband’s father was a fraternal twin. My brother, my nephew and my husband’s niece have identical twins.

Identical twin girls

Yes. My mom’s a twin, I’m a twin, and I had twins ❤️

Two sets of fraternal on first cousins dad’s side. And my nephew has a set as well.

Yes on my mom’s side and my biological dad’s side. But I ended up with the twins that do N🚫T run in families lol I have mono/di twins. Which come from the same exact embryo and split into two. Lol

Yes, my dad and his grandmother are both sets of twins. I had twins. My husband fathers side had both great grandparents as twins. 2 of their 8 kids had twins, my SIL has twins, his mother has multiple sets of twin cousins.

Yes. Great-uncles were, my mom’s a twin, I have twins. I was told my whole life that I was next. It was true 😳😃

My great grandmother (who I was named after) had b/g twins, skipped 2 generations, then I had b/g twins

I’m a twin, my dad’s a twin, and I have twins! I also have twin great uncles and a cousin pregnant with twins!

Are You a New Twin Parent?

Check out Natalie Diaz’s book:
What To Do When You’re Having Two
The Twin Survival Guide From Pregnancy Through the First Year

what to do when you're having two book

In What to Do When You’re Having Two: The Twins Survival Guide from Pregnancy Through the First Year, national twins guru and founder of Twiniversity (and twin mom herself!) Natalie Diaz provides a no-holds-barred resource about life with twins, from pregnancy and birth all the way through your duo’s first year of life.

Accessible and informative, What to Do When You’re Having Two
 is the must-have manual for all parents of twins.

Yes they run in our family. They also walk, skip and jump. (But also yes, we have many twins on my maternal side).

Yes! Oddly all identical twins (4 sets)! Mine were the first fraternal twins😊

On both sides: paternal great-grandfather was half of a b/g fraternal set; identical set on maternal side. I know have a fraternal g/g set.

Fraternal twins are like winning the genetic lottery with double the fun, as they run in families due to a tendency for women to release multiple eggs during ovulation. On the other hand, identical twins are like a genetic surprise party—they’re rare and more about luck than family history, happening when a single fertilized egg decides to divide into two. So, whether you end up with two peas in a pod or a duo of genetic doppelgängers, the marvel of twins adds an extra splash of excitement to the family tree!

Latest Twiniversity Articles

Subscribe to Our Mailing List

/ /

Staying Informed

Recent Posts