From MacBeth's Opinion, an article in the NY Times on Chaminade High School:

At a Boys’ Catholic School, Tradition Fuels Demand

"UNLIKE most Roman Catholic schools in the New York area, which embrace students regardless of their religion, Chaminade High School here requires a baptismal certificate to register.

“No exception,” said the Rev. James C. Williams, a cherub-faced priest who is the school’s president. “We advertise that pretty clearly because this is who we are. I don’t have room for all the Catholics who want to be here.”

"Chaminade, founded in 1930 and now the Island’s only all-boys Catholic school, has thrived by staying unabashedly Catholic and traditional."

Actually the school is not particularly traditional in many ways, but it is solidly Catholic.