Were They All Catholic?

Elaine Lafferty has a nice piece in the Irish Times about American attitudes toward terror vis a vis Europe’s. But there’s one statement that I find odd:

Thousands, not hundreds, of civilians were killed; the estimate in New York is that 30,000 to 40,000 children lost a parent in the attack on the World Trade Centre.

Am I missing something? Last I heard, the death estimates were about three thousand, give or take.

First of all, surely not all of the dead were parents. But even if they all were, and ignoring the cases where both parents were killed (hopefully rare), that would average out to over ten kids apiece. So who came up with this number and how was it derived?