What Are Fraternal Twins?

Benna Crawford
Fraternal Twins

After the shock wears off and the frantic planning for doubling up begins, you'll probably wonder if the impending duo are as similar as any siblings or exact mirror images of each other. Chances are, your twins are fraternal. That gives you, and them, the best of both worlds.

Fraternal Vs Identical Twins

Fraternal twins occur when a woman releases two eggs, or zygotes, at ovulation instead of one, and both are fertilized with individual sperm. The fetuses gestate together in the same pregnancy; they are siblings with all the family resemblance to each other that siblings have. Fraternal twins are not DNA clones, they each have their own DNA, their own amniotic sac, their own placenta, and are no more alike than any other set of siblings; other than the fact that they share a birth date (most of the time at least). Dizygotic or fraternal twins may be different genders. Identical (monozygotic) twins who are born from the same split fertilized egg, are DNA clones and are always the same gender. There are a few other interesting things that are unique about fraternal twins.

Two-to-One Odds

Peaceful Newborn Twins

You can calculate the odds of having twins but there's always some uncertainty. Columbia University points out that the twin birth rate is increasing. In 2013 the U.S. twin birth rate was 33.7 per 1000 births, way up from 18.9 per 1000 in 1980. Much of the increase is due to fertility therapies such as in-vitro fertilization (IVF), which is used by couples to increase the chances of becoming pregnant. The hormone stimulations also increase the chance of releasing multiple eggs. That can mean multiple fertilizations and multiple births. These twins are always fraternal. However, IVF also increases the chance that one fertilized egg will split into two - and thus you'll have identical twins.

Skipping a Generation

Identical twins are never hereditary. So if your parents had identical twins, you have as much chance of conceiving identical twins as anyone else in the world does. However, there is a genetic predisposition to hyperovulation. If you 'hyperovulate,' or release two eggs at one time, this makes it more likely that you will have fraternal twins. It seems that twinning skips a generation because the gene doesn't express itself in men. In other words, men don't hyperovulate, only women. So while women in the family may hyperovulate and thus are more likely to have twins, sons merely pass the gene on. Keep in mind though, twins are complicated and merely being predisposed to hyperovulation doesn't mean you'll have twins. It just increases the chances.

However, a woman who is a fraternal twin, or who has twin siblings, is two and a half times more likely to have twins herself, according to Columbia University experts. You have a higher probability of twins if you are of African descent, a lower probability if you are of Asian descent. Older women and women who have already given birth are more likely to carry fraternal twins.

BFF Fraternals

fraternal twins

Fraternal twins share about 50 percent of the same DNA. They may be extremely close - even sharing a secret language or inexplicably close bond. However, don't count on it just because they're twins. Like anyone else in the family, they may fight, argue, and be as close or not close as they are with any other sibling in the family. Regardless, experts generally agree that it's important to let twins determine their attachment needs at their own pace.

Reaching Milestones

It's important to remember that because fraternal twins are two different people who happen to have been born at the same time, when it comes to milestones. It's not inconceivable that one twin will walk at 9 months, while another waits until their one year birthday. As long as they are developing within the range of normal, experts say there's nothing to worry about.

Success Strategies for Managing 'Twindom'

From the beginning, prepare your fraternal twins to share a special bond but grow into confident separate people. There are a variety of ways you can facilitate this.

Treat Them As Individuals

When you have two newborns, you tend to do things on autopilot. You feed them at the same time, have them nap at the same time, and dress them at the same time. However, as they grow, be wary of treating two little personalities like a single entity.

  • Avoid comparing the twins physically, academically, athletically, artistically or socially.
  • Celebrate each twin's triumphs and skill masteries but don't compare them. Fraternals don't always hit milestones in tandem. If Dahlia learns to write her name, surely Dashiell draws a mean dump truck or is good at helping with the groceries. He'll have the name thing down by Christmas.
  • Skip dressing them alike. When they are babies, it might be cute, but if they are the same gender and you dress them alike, people will forever
  • Call your double dish by their individual names. "The twins" is not a person; it's a shortcut. Mika the budding poet, and Jenny the horse trainer are persons and each deserves her own identity.

Encourage Independence

While you'll want to listen to your twins' and how they feel about being separated, it's also important to take opportunities to promote their independence from each other.

  • Resist a school that mandates twin separation as a policy. Twins and their parents have a better handle on when they are ready to split up.
  • Encourage all bids for differentiation with a very Zen attitude of acceptance. People will compare your fraternals, whether you find that fair or not. A child who takes the initiative to define her own uniqueness is less vulnerable to outside evaluations and judgments.
  • Prepare to double the mileage wherever possible, as one twin falls madly in love with softball and the other becomes a tennis pro-in-training.
  • Teach them to deal with inevitable questions themselves. When you (or they) are asked if they are twins, encourage them to simply say, 'Yes.' They can also be more vague and answer with something like, 'We're brothers.' This is empowering and lets them learn about setting boundaries.

Help Them Bond

The trick with twins is carefully constructed balance. Encourage them to bond with each other and do what you can to discourage sibling rivalry as with twins in particular, it can be intense. You also want to encourage them to bond with the rest of the family.

  • Teach twins to look out for each other and enjoy each other's achievements when they are small. Have them find their shoes and fetch their twin's shoes as well. Give one child a treat with a second to deliver to his twin.
  • Take them to each other's games and events as #1 fans.
  • Integrate the inseparable twosome with siblings by letting older sibs help with easy tasks and one-on-one child-minding to give you a break and establish the family hierarchy.
  • Give each twin "alone" time with parents. Fraternals are not a single unit and each one needs parent bonding.

Twins With a Difference

Fraternal twins are a twofer. They may exhibit all the behaviors of indistinguishable intuitively linked carbon copies. Or they may be as chill and independent as their other non-twin siblings. Most are a mix of alike and apart that will amaze and astound you. The one sure thing is, you're in for an adventure. Try to get some sleep.

What Are Fraternal Twins?