The new court hearing has been scheduled for Thursday, according to the AP.
“Charlie’s got a chance to get better here,” Yates told BBC Radio 4 before Monday's hearing.
Charlie's parents delivered a petition Sunday to Great Ormond Street Hospital in London, calling for their son to be transferred to another hospital to receive care.
It came as two U.S. congressmen have promised to introduce a bill that would give the baby and his parents lawful permanent residency status in the United States, so the boy can undergo treatment in the country.
“Despite Charlie's heartbreaking condition, his parents have refused to give up hope. They have advocated for him fiercely,” Reps. Brad Wenstrup (R-Ohio) and Trent Franks (R-Ariz.) said in a statement last week. “Should this little boy to be ordered to die — because a third party, overriding the wishes of his parents, believes it can conclusively determine that immediate death is what is best for him?”
The petition and the prospect of U.S. legislation are the latest in a months-long battle over whether Charlie should be taken off life support or receive a new treatment that the hospital has previously said would be futile. Charlie's parents also have received support from Pope Francis and President Trump, with hospitals in Rome and New York offering to take Charlie.
“He's our son. He's our flesh and blood. We feel it should be our right as parents to decide to give him a chance at life,” Yates told reporters Sunday, according to BBC. “There is nothing to lose. He deserves a chance.”
The hospital had said earlier that the treatment the baby's parents are seeking is unjustifiable and “would prolong Charlie's suffering.” Justice Francis ruled in April that withdrawing life support was in the boy's best interest. The ruling has kept the hospital from allowing Charlie's transfer overseas.
Charlie's parents have appealed and lost. The lengthy legal battle seemed to be over when the European Court of Human Rights rejected the parents' appeal last month. The hospital had intended to remove Charlie off life support on June 30.
But things took a turn last week when the hospital asked England's High Court to rehear the case after researchers at two other hospitals shared new evidence about the treatment.
“We believe, in common with Charlie's parents, it is right to explore this evidence,” Great Ormond Street Hospital said in a statement Friday.
It's unclear from the statement which two hospitals have shared the new evidence, but according to the Catholic News Agency, a team of seven doctors from across the globe alerted the British hospital of new, unpublished data suggesting that the experimental drug that Charlie's parents are seeking could improve his condition. One of those doctors is a researcher and neurologist from Bambino Gesù Children’s Hospital in Rome, which has previously offered to treat Charlie.
Clinicians from the Vatican-owned hospital's neurosciences department said tests in mice and patients with similar, but not identical, genetic condition as Charlie's suggests that the boy's condition could significantly improve, the Associated Press reported.
Another hospital, New York-Presbyterian Hospital/Columbia University Irving Medical Center, told The Washington Post last week that it would admit and evaluate Charlie “provided that arrangements are made to safely transfer him to our facility, legal hurdles are cleared, and we receive emergency approval from the FDA for an experimental treatment as appropriate.” The hospital also offered to ship the experimental drug to Great Ormond Street Hospital.
Charlie was born in August with infantile-onset encephalomyopathic mitochondrial DNA depletion syndrome, or MDDS, according to court records. The rare genetic condition has kept him from being able to see, hear, move or breathe on his own.
Chris Gard told reporters Sunday that the U.S. hospital where they want their son to be treated has doctors who specialize in Charlie's condition. It's unclear whether that hospital is New York-Presbyterian.
“This has a chance. It's got up to 10 percent chance of working for Charlie, and we feel that that's a chance worth taking,” Connie Yates said of the treatment. “We've been fighting for this medication since November. We're now in July.”
An online campaign has raised about $1.7 million to send Charlie to the United States.
This story, which was originally published July 9, has been updated.