Identical twin sisters Brittany and Briana plan to raise their children as siblings on Extreme Sisters

Identical twins Brittany and Briana do everything together – they got engaged together, Brittany and Briana and now they are mothers!

Brittany recently welcomed baby Jett with her husband Josh and now Briana and her husband Jeremy are parents to another boy – baby Jax.

Stream episodes of Extreme Sisters for free on 9Now.

While most would assume that Jett and Jax are cousins, the fact that both of their parents are identical twins actually makes them genetic siblings, a rare phenomenon known as quaternary twins.

In an episode of Extreme Sisters – which you can stream for free on 9Now – the sisters reveal their plans to raise their children as siblings.

Brittany, Briana and their husbands all live in one house and they plan to raise their children as one family.

"We're settling to our life as six of us and parents of quaternary twins," Brittany told cameras.

While many would think Brittany and Briana are technically aunts to each other's children, they actually consider themselves mothers to both Jax and Jett.

WATCH: Identical twins want to fall pregnant at the same time - with the same man

"We're still working on what our children will call all of us," Briana explained.

"Mummy and 'aummy' – aunt and mum combined – works really well," Brittany added.

But the sisters were still working on what the kids would call their dads.

"Is it going to be daddy and 'dadsy' or daddy and 'duncle'," they contemplated.

The sisters took combined motherhood to an extreme level by breastfeeding both babies.

"The best thing about having two mums in the house is that we have four boobs," Brittany laughed.

"We can actually help each other nurse our babies, which we do.

"We breastfeed each other's babies because we feel like they're both of our babies."

WATCH: Parents of 14 reveal the astonishing amount they spend on monthly groceries

To watch Brittany and Briana's full story watch 'Ep 8 Our Happily Ever After' on Extreme Sisters on 9Now.

Stream episodes of Extreme Sisters for free on 9Now.