Do twins come from Mom or Dad?

Joe Rawlinson by Joe Rawlinson - August 7, 2023

Do twins come from Mom or Dad?

Well, we know that twins grow inside of Mom and she does the lion’s share of all the work in that process.

But what about family history or genetics? Will Dad’s history or that of the Mother determine if you’re having twins?

This question requires that we go back to our high school biology class to remember how babies are made.

If you remember, there’s an egg from the mother and a sperm from the father. When those come together, it creates the baby.

With twins, you have certain circumstances that caused them to become twins.

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Identical Twins

Let’s start with identical twins.

Identical twins are completely random. It’s not based on family history or genetics.

Identical twins form when a single fertilized egg splits and forms two embryos. Now in this case, it’s not because of mom or dad. It’s just beautiful luck that creates identical twins.

So who “causes” identical twins? Mom? Dad?

The answer: neither one. You’re just lucky!

Fraternal Twins

Next are fraternal twins or non identical twins. In this case, Mom’s side of the family has more influence than the father.

Instead of a single fertilized egg splitting into two, you have two eggs that are independently fertilized.

Why would Mom have two eggs at the same time ready for fertilization?

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It could be due to several different factors.

First is that Mom released two eggs at the same time. Typically, a mother will release one egg every cycle that is available for fertilization.

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However, in the case of fraternal twins, the mother may have released two eggs.

As Mom ages, she may tend to release more than one egg every cycle. So the older the mother, the more likely that she may have non-identical or fraternal twins. This is one reason so many celebrities seem to have twins.

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Another option is that the mother has a family history of hyper ovulation where mom releases more than one egg every cycle. So if mom has a history of that, or mom’s family has a history of that, you may be more likely to have fraternal twins.

We also have the wonders of modern medicine. If families are having a hard time conceiving and having children, parents may decide to go for additional measures to help encourage conception and pregnancy.

When you start to involve modern medicine, the game changes completely, it doesn’t really matter what mom’s family history or dad’s participation is.

Because if mom is taking some medication to help her ovulate, she may release more than one egg. That could cause potentially fraternal twins or triplets or more.

4 Critical Mistakes Expectant Twin Parents Make

Parents may use in-vitro fertilization (IVF) to get pregnant. This is where an embryo is created outside of mother’s uterus and then implanted in the uterus. Oftentimes parents choose to embed more than one embryo in the uterus with the hopes that they take. That could lead to more than one baby: twins, triplets etc.

Dad’s Role in “Creating” Twins

So of all I’ve explained so far, dad has little to no say in if they’re twins or not. Sorry, mate.

Of course if mom and dad are the couple are deciding together that they want to embed more than one embryo through in-vitro fertilization, then obviously dad has a say in things.

Are twins hereditary through the father? No.

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When you look at spontaneously conceived twins, dad’s family history, genetics, and opinions really have nothing to say with whether you have identical twins or fraternal twins at all.

The Bottom Line about Having Twins

If you have identical twins, congratulations, you won the twin lottery. It’s not because of mom or because of dad. It’s just random and a beautiful thing. As we know, we have identical twin girls.

If you have fraternal twins or are expecting fraternal twins, it could be because of Mom (age, hyper ovulation, medical assistance, etc.)

So there you go. Are twins because of Mom or because of Dad? Well, it depends.

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How about about you? Do you have identical twins or fraternal twins? Go ahead, leave a comment below and tell us what you have and when you found out what you would be having.

Further Reading

Dad's Guide to Raising Twins book
Don't forget to pick up a copy of the definitive guide to raising twins. "Dad's Guide to Raising Twins" was written for fathers of twins to help guide you through the first several years with twins. Click here to learn more about the book and get your copy.

24 thoughts on “Do twins come from Mom or Dad?”

  1. I’m an identical twin! Sharon Kay and Karen Rae. We are in our sixties and have THOROUGHLY been BLESSED to be twins. She is my best friend, wombmate, and we still like dressing alike when we visit each other! When we were in high school we graduated 10th in our class. We took different courses and still had the same GPA.

  2. We have identical twin girls April and Alice. Found out early on that it was twins but thought that was a big enough surprise. So we waited till birth to find out the sex.

  3. We have identical mirror twin girls (identical twins – one right handed with hair that parts on the left, the other left handed with hair that naturally parts on the right). Lottery won for sure. Amazing to see so much love between them

  4. I’m expecting twins in August – identical twin boys! Was a huge shock finding out, but now we are very very happy and excited. Don’t know much about twins and will soon find out.

    • @Trina – congratulations on your upcoming twins! Twins were a shock to us too. Best of luck to you as you prepare for their arrival.

  5. We have fraternal Boy/Girl Twins! They were definitely inherited genes! My mother’s Mother bore fraternal twin sons…sadly, it was during a time there weren’t Drs. or facilities to care for her.
    She died 2 weeks after childbirth. There were 4 children, including the Twins.
    Thankfully, all of the siblings were raised by relatives and succeeded in life!
    They say fraternal Twins skip a generation. Certainly did in my case

  6. Good article! I have an identical twin sister and my brother and sister are fraternal twins. My son and his wife just gave birth to fraternal twins. So we are twinning all over the place. Lucky and very blessed!

  7. I also won! Twice over! I have two sets of identical twins. First set girls who are now 8 born at 40 weeks and my second set are boys who are 3 born at 26 weeks.

    Check out the twin convention usually held in August!


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