The title of this post is the caption beneath the Instagram picture of two boys who look very much alike. Are they twins? Sort of. Mirriam-Webster defines "quaternary" as "of, relating to, or consisting of four units or members." Which brings us to an explanation of these's babies' relationship.
Identical twins Brittany and Briana met identical twins Josh and Jeremy at a twin festival in 2017. A year later, Brittany married Josh and Briana married Jeremy in a double wedding ceremony. Now they are all named Salyers. The sisters became pregnant a couple of months apart. Jett Salyers was born to Brittany and Josh in January of 2021. Jax Salyers was born to Briana and Jeremy in April of 2021. The two boys were produced by different couples, but each couple has DNA identical to the other couple.
So the two boys are listed as cousins on the family tree. Double cousins, to be precise. But since their parent are identical twins on both sides, any genetic analysis would identify the boys as siblings. Their closeness in age, and the fact that they all live in the same house, would lead any future classmates who see them to consider them as twins. Read more about the four Salyers twins and their sons at the New York Post. -via Boing Boing
The only question would be how do the sibling cousins distinguisch their parents from their aunties and uncles? ;-)