Quaternary Twins: Pairs of Identical Twins Marry and Have Sons Who Are Genetic Brothers

Two pairs of married identical twins from Virginia have welcomed sons born within months of each other, who are technically and legally cousins and genetic brothers or quaternary twins.

Identical twin sisters Brittany and Briana met identical twin brothers Josh and Jeremy Salyes in 2017 during an Ohio Twins Days Festival. It didn't take long for the couples to fall in love, get married, move into the same house, and start a family together.

In an interview with Today, Brittany said that the four of them planned everything about their lives together because their husbands also understand the "twin bond" so well, just like her and her sister. The decision to have babies within months of each other was also a conscious choice, making Jett and Jax a rare pair of twins.

Read Also: Vanishing Twin Syndrome Surprises Woman With Miracle Twins After Losing Her Babies, 16 Miscarriages

What are Quaternary Twins?

Quaternary twins are the offspring of two pairs of identical twin parents whose births are spaced less than nine months off each other. While they do not share parents or do not come from the same womb, the offspring carry identical DNA that makes them genetic siblings.

According to Prof. Laura Almasy of the University of Pennsylvania, though Jaxx and Jet are technically cousins, they have drawn the same DNA from separate but identical sources. On the other hand, the DNA of cousins is not drawn in this manner. Thus, it's expected of the cousins to share DNA like full siblings.

Jax, the son of Briana and Jeremy, celebrated his first birthday last January 2022, while his quaternary twin, Jett, born to Josh and Brittany, will be turning one in April.

The babies' mothers said they discussed and hoped for overlapping pregnancies as this was as rare as their marriage to their husbands. There are less than 300 quaternary marriages in all of the world's history.

While Brittany laughed at the suggestion that they timed the conception of their children perfectly, she admitted that the pregnancies were something that they wanted to experience together. As twins, they have shared a lot of milestones in their lives, including their double wedding to Josh and Jeremy, so this was an ideal arrangement.

Second Baby Plans

Meanwhile, Briana said they are already thinking about having their second babies together. However, it might not happen anytime soon since their quaternary twins are still relatively young.

The Salyes twins have quite a following on their social media page, and Brittany said they get both supportive and critical comments. Some people find it strange that the twins want to do everything together, but the pairs said they ignore the negative feedback and focus on the positive.

Jeremy said that it's quite rare for them to do things separately because "together" has been how they led their lives as kids. The sisters are the same way as well.

Aside from raising their quaternary twins under one roof, the pairs of identical twins also run a wedding events business together. The family also star in their own TLC reality TV series "Extreme Sisters."

Related Article: Former Conjoined Twin Grows up To Become an Influencer Who 'Channels' Her Sister