By necessity, Carmen and Lupita are closer than most 16-year-old sisters.
Their priorities are the same - schoolwork, friends and getting a driving licence.
But now they must confront a much more life-changing decision, when they should be separated by surgery.
Most conjoined twins die within just a few days of being born.
But the pair, who were born in Mexico but came with their family to Connecticut in the US as babies, have survived against the odds.
The girls are attached at the chest wall down to the pelvis where the spines meet.
They each have a heart, lungs, two arms and one leg each, Carmen the right and Lupita the left.
But after 16 years of sharing every waking moment together, they must now contemplate a new destiny.
Doctors have advised they must be separated by surgery or face serious medical issues in the near future.
But they told the Hartford Courant, the concept is devastating.
"We're so dependent on each other," said Lupita.
She said she doubts they could "get used to not being dependent on each other."
The family are also feeling pressure from elsewhere.
They fear they may be forced to leave if President Donald Trump axes the work permit programme that has allowed them to stay.
The physical and financial practicalities of being separated seem overhwhelming.
But for Carmen and Lupita said their biggest fear is of losing each other.
Carmed said: "...because we've been so used to, like, being together.
"I don't think there'd be, like, a point."
