Lawyers are spending the weekend studying the latest expert reports on Charlie Gard as a High Court judge prepares to decide whether to let the terminally-ill baby travel to the United States for treatment.
Mr Justice Francis is scheduled to analyse the most recent evidence at a trial starting in the Family Division of the High Court on Monday.
Chris Gard and Connie Yates want the judge to rule that their 11-month-old son, who suffers from a rare genetic condition and has brain damage, should be allowed to undergo a therapy trial overseen by a specialist in New York.
Specialists at Great Ormond Street Hospital in London, where Charlie is being cared for, say the therapy is experimental and will not help.
They say life support treatment should stop.
Earlier this week the American specialist, Michio Hirano, a professor of neurology at Columbia University Medical Centre in New York, travelled to London to examine Charlie for the first time and discuss the case with Great Ormond Street doctors.
Lawyers say they will examine specialists reports, and data from fresh scans, during Saturday and Sunday.
The judge considered preliminary issues at a hearing on Friday.
Barrister Katie Gollop QC, who leads Great Ormond Street's legal team, told him that a report on a new scan made for "sad reading".
Charlie's parents reacted furiously to the news.
They said they had not read the report.
Ms Yates burst into tears and Mr Gard yelled "evil".
Charlie's parents, who are in their 30s and come from Bedfont, west London, have already lost battles in the High Court, Court of Appeal and Supreme Court in London.
They have also failed to persuade European Court of Human Rights judges to intervene.
But the couple say there is new evidence and want Mr Justice Francis, who in April ruled in favour of Great Ormond Street and said Charlie should be allowed to die with dignity, to change his mind.
Charlie's parents, who are in their 30s and come from Bedfont, west London, have already lost battles in the High Court, Court of Appeal and Supreme Court in London.
They have also failed to persuade European Court of Human Rights judges to intervene.
But the couple say there is new evidence and want Mr Justice Francis, who in April ruled in favour of Great Ormond Street and said Charlie should be allowed to die with dignity, to change his mind.