Skip to main content

Everything you want to know about fraternal twins

If you think you might be pregnant with fraternal twins, we'll answer your questions and concerns

Pregnant woman on a bed.
Ground Picture / Shutterstock

Finding out you are having twins would be quite a shock if you weren’t expecting it. But once you know that’s what you’re having, you can’t help but wonder what you will have. Identical? Fraternal twins? Parents of twins immediately want to know what type of twins are in there. Rightly so, because buying two of everything will be both adorable and expensive. Here’s what you need to know if having fraternal twins is in your future.

The fraternal rundown

Two babies looking at the same screen.
Jelleke Vanooteghem / Unsplash

What are fraternal twins?

The most basic way to explain how you get fraternal twins is when two separate eggs are fertilized by different sperm. The more scientific term is dizygotic twins, but are known as non-identical twins. To round things out, identical twins, known as monozygotic twins, happen when one egg is fertilized from one sperm and then splits to create two mini humans.

Fraternal twins statistics

Having twins at all is still relatively rare. For every 100 births, at most, there will be a chance of twins (or triplets or more). When it comes to having twins, the chances of them being fraternal are the most common. Out of 1,000 sets of twins, around 23 of them will be fraternal, compared to only 3 or 4 out of 1,000 births being identical twins.

Why fraternal twins don’t look alike

Giving birth to fraternal twins is no different than having children one after another, genetically speaking. They are two eggs, two sperm, two embryos, two placentas, and two inner sacs. It is two different humans that happen to be growing at the same time.

Fraternal twins will share the same amount of genetic material as regular siblings, which is why they don’t look exactly alike as identical twins do. Each twin shares half of everything, just like siblings that were carried at different times.

Factors that affect having fraternal twins

Two siblings lying on the floor watching tv together.
nazar_ab / iStock

How fraternal twins can happen

  • If the mom is a fraternal twin, her chances of having fraternal twins is 10%.
  • Older mothers have a higher chance of having fraternal twins.
  • Race does play a part in the odds.
  • Being a taller female that weighs more.
  • Having already given birth.

Twins run in the family, especially so if Mom is a fraternal twin herself. Waiting to have kids later in life will bump up your chances of having children. A woman over 35 doubles the odds of having fraternal twins. Women who give birth in their 20s have the lowest chance of fraternal twin birth.

Race does come into play for fraternal twins, with those of Asian descent having the least chance and Black African American women having the highest chance for this type of birth.

While not entirely scientifically backed, having a diet heavy in sweet potatoes and yams and being a taller woman may increase the odds. Already being pregnant and having children is supposed to add to the chances, as well.

Risk factors of carrying fraternal twins

A pregnant woman holding her belly and a glass of water.
Cottonbro Studio / Pexels

Having any form of multiple births can pose a risk for the mother. Once you find you are having twins, your doctor will monitor you a little more closely.

Risks of having fraternal twins

  • Increased risk of placenta previa.
  • Greater chance of gestational diabetes.
  • Possibly longer and harder postnatal recovery time.
  • Lower birth rate for the babies.
  • Higher chance of premature birth.
  • More likely to have a caesarian.

To be fair, these could happen having any form of multiples, or having any child depending on your personal history. But it’s best to be as prepared as possible.

If you’re having multiples, you will have more frequent checks than a woman carrying one child. You might have additional ultrasounds, general appointments, and special monitoring if you are having twins. The heightened attention starts around the third trimester.

Other fraternal twins facts

Two babies in a double stroller.
Natalya Lys / Shutterstock

Needing medical assistance to become pregnant increases your chances

Medical intervention for having children has come a long way. Since the first test-tube baby birth in the U.S. in 1981, fertility methods and treatments have made multiple births more common. Thanks to implanting multiple embryos to hope one survives, there has been a jump in more than one sticking. 

You will likely deliver early

Don’t worry if you don’t carry to full term when having twins. Most twin births happen by week 38, with week 32 being the minimum goal to get to. Week 36 is the average week of delivery, so if you’re carrying twins, know you need to be prepared sooner rather than later.

To know the type of twins

If you can’t wait until the birth to know what type of twins you’ll have, tests will need to be done. A DNA test will determine if your set of babies is identical or fraternal. Looks are a tip-off, as fraternal twins won’t look exactly the same when looking at features like eye and hair color. If you have one of each gender, that will tell you immediately, as only identical twins are the same gender.

Once the shock of knowing you’re going to have two little ones to chase after settles down, learn a bit about having fraternal twins. Know it doesn’t have to be as stressful as you think and won’t be that much different from being pregnant with one child. We can’t say that having two toddlers at once won’t put you a little on edge, but carrying fraternal twins shouldn’t be so bad.

Dannielle Beardsley
Dannielle has written for various websites, online magazines, and blogs. She loves everything celebrity and her favorite…
Flying while pregnant? This is what you need to know
Know these guidelines about flying while you're with child
A family walking in an airport

Maybe you have to travel for work. Maybe you already had a vacation planned before finding out you were pregnant. However you got here, the reality is you're pregnant, and you have to get on a plane. Can you fly if you are pregnant, or is it on the list of no-no's, like soft cheese and deli meats? Whether you already booked that plane ticket or not, there are a few things about flying while pregnant to know. 
Traveling while pregnant
Let's break it down by trimester, so you know where you'll be when you take your trip.

First trimester travel
The first part of your pregnancy is usually OK to travel during. Most women don't start to show yet, feel pretty normal, and aren't physically restricted by a beach ball blocking everything they do. But there are two things to know if you fly in your first trimester.

Read more
The ultimate nursery checklist of everything you need (and nothing you don’t)
Nursery essentials babies need when they come home from hospital
White nursery

There are so many exciting moments during a pregnancy, but one which many parents-to-be look forward to is planning the nursery. Putting together baby's nursery is such a thrilling time. It's packed with important decisions like the color of the nursery, and of course, the theme. Then, there's the shopping for all the necessities baby will need when your little one comes home from the hospital.

Getting ready for the birth of your child is exhilarating, but it's also overwhelming. Deciding on the nursery essentials can be daunting, especially if this is your first baby. Shopping for baby is expensive as well. Before heading to a baby store or shopping online, it's prudent to have a nursery checklist. Using a checklist to outfit the nursery will ensure you'll have what you need and won't waste money on things you don't. So, let's get shopping because we've got the nursery checklist must-haves along with the items you don't need.
Nursery checklist

Read more
Glass vs. plastic baby bottles: Here’s what doctors have to say
How to choose the best bottle for your little one
A cluster of different baby bottles in a bowl.

Having a baby can be overwhelming, especially for first-time parents. It means making endless decisions about day-to-day activities and how they can impact the baby's safety. Even something as simple as choosing the type of bottle to use becomes an important decision. Glass vs. plastic baby bottles: Which is a healthier choice?

A baby's bottle is a vital purchase, and it's certainly worth exploring all the factors when it comes to glass or plastic baby bottles for health, convenience, and cost concerns. There are trade-offs to consider with each. So, here's what parents need to know when it comes to glass vs. plastic baby bottles.
The scoop on plastic baby bottles
With all the concerns around chemicals in plastics, it's natural for parents to wonder if anything from a plastic baby bottle might find its way into their baby's milk.

Read more