Lawyers say Jewish schools may face a barrage of battles from parents contesting practice-based admissions decisions.
This follows the case of Kayleigh Chapple, the non-observant Jewish girl denied a place in Liverpool's King David High School.
Solicitor Jack Rabinowicz, an expert in education law, says the move from descent-based criteria is going to lead to "a lot of disagreement and dispute.
"I think the problem for schools is that we are changing from what used to be regarded as a simple admissions basis to one which is more practice-based - and there are lots of arguments about how exactly one is a
Mr Rabinowicz, who has represented Catholics - a faith in which practice-based admissions disputes are common - says potential disputes will not be avoided if schools lower the bar of criteria try to include volunteering or cultural activities.
Most of these disputes will be dealt with by an appeal panel, either at the school or run by local authorities. But Mr Rabinowicz says this will not protect some cases going to the High Court in the form of a judicial review, which could cost schools or parents a minimum of £50,000.
As the Chapple family lost their appeal three weeks ago, two paths now lie before them. The local government ombudsman can revisit the decision of Liverpool Council's Admissions Appeal Panel, which King David had appointed to decide on disputes with parents.
But a judicial review can quash an admissions decision and force admission to a school, even one oversubscribed, as occurred in the JFS case. David Wolfson QC, who represented the Board of Deputies in the Supreme Court JFS hearing, says judicial reviews might now be hard to win unless parents can demonstrate the admissions policy has not been applied correctly.
He said: "The only other challenges are if the policy is irrational or unlawful. It's hard to see how practice-based admissions are irrational, because it's a policy that has been put in place by a large number of schools. In light of the Supreme Court judgement, a claim that a policy was unlawful would effectively raise the same issue as was brought up with the JFS case."
Mr Wolfson, who grew up in Liverpool and himself attended King David High School, said that the Chapple case threw into sharp relief the difficulties now facing Jewish schools.