It depends on what the term "illegitimate" means.
The term "illegitimate" is much more expansive than the Hebrew term "Mamzer" which refers to a child born out of an incestuous relationship or a child born to a married woman and a man not her husband. The father has no obligation to a Mamzer. The father does have an obligation to any other child that he fathers (regardless if it falls within the Western definitions of legitimate or illegitimate).
I thought it was fairly well-known, but didn't know it was illegitimate.
Generally speaking, no.
my Jewish brother is the illegitimate offspring of Blondie and Hitler.
He wasn't Jewish. There were rumors that his mother was the illegitimate daughter of her mother's Jewish employer, but no serious scholars believe this. The most popular rumour is that his paternal grandfather was a Jew ... but serious scholars think it is an urban legend.
No, she is not However one of her family members might be Jewish because their mothers or fathers were born Jewish.
The apocalyptic Jewish sect are considered as the first century church fathers.
Yes she is. Her grandma and grandpa are Jewish. Jewish tradition makes the judgment call depending on a person's mother. If the grandmother is Jewish, the daughter would be Jewish, and then a grand daughter would also be Jewish, in turn.
Yes. She was the daughter of Polish Jewish immigrants to the U.S.
Alice Walton, a daughter of Sam Walton, who founded Walmart, is not Jewish
Sometimes fathers are referred to as abba.
Jewish (from mothers side) and Italian (from fathers side)
Visiting the sick is considered a very important Mitzvah (obligation) in the Jewish religion, wherever one lives in the world.