An interesting interpretation of these 4 sons/daughters follows:

The Wise Child represents the Immigrant.

S/he knows and follows customs.

The Wicked Child represents the 1st Generation born in the USA.

S/he knows the religion, but chooses not to practice it. Tries to assimilate.

The Simple Child represents the 2nd Generation, grandchild to the Immigrant.

S/he remembers Grandparents doing rituals. Wants to keep traditions, but doesn't know them. Usually gives up.

The Child Who-Does-Not-Know-What-to-Ask represents the Totally Assimilated.

They may not know they're Jewish, or what it is or means.