The parents of 3-year-old conjoined twins face a difficult decision — because their daughters are growing too big for the heart they share, Sky News reported.

Emma and Taylor Bailey, who live in Phoenix, Ariz., with their parents Mandy and Tor, were born with the same heart and liver.

They were only expected to live for 15 minutes after doctors predicted their lungs would crush their heart as soon as they took their first breath.

But the pair, who are fused from their breastbone to their belly button, survived and have enjoyed a happy and healthy life.

However, as the girls grow, their shared heart is becoming weaker and could fail if they are not separated.

Doctors have suggested the operation should take place in one to two years' time, with both girls likely to need heart transplants and one a new liver.

The girls' parents said there was "a tiny window of time" to decide on whether to go ahead with the surgery.

"We have to get it completely right, if we wait too long then the operation cannot go ahead," Mandy said. "We know we have to make difficult choices. We understand the risks. But we also understand the outcome if we don't do anything."

If the operation is successful, it will be the first time twins born with one heart will have been separated.

SOURCE LINK: Sky News