Dror, You understand why assimilation bothers us: "the desire of many parents to see their children preserve the tradition" - So how can you say it is like cancer or heart disease? If assimilation struck only the old, we would not worry. The reasons for assimilation are intimately tied into the question you identify as more important: What it means to be Jewish--and in the American context, there will be no solution to assimilation without finding meaningful reasons for a Jewish future. Concern about assimilation focuses the attention on the meaning of identity. The issues you lump as "demography" are entirely different concerns between Israel and here, and it is sleight of hand to combine them. And for everyone who is about to talkback about how debating the loss of ancient tradition through assimilation is somehow "racist," please go read more about human history, or, say, read "The Dignity of Difference" by Jonathan Sacks.
Poland's central bank head calls story of Nazi train find a hoax (Reuters)
from the article: A Jew is not a number