Hi Allen,
My older brother (American, ethnic-Jewish) married a German woman, and they raised their two children in the U.S. in a household comfortably -- not forcedly -- speaking English, German and Hebrew (my brother is multilingual and speaks German fluently). The kids, now 16 and 19, are bilingual in German and English, speak Hebrew passably well, and they are comfortable in their own skins whether in the U.S., Germany or Israel .
My younger brother married a Puerto-Rican/Latina woman, and they are raising their 13-year-old son in a U.S. household. The lad's mother speaks to him in Spanish as much as she can and wants desperately for him to embrace his Latino-Spanish roots. His father (who doesn't speak Spanish) speaks to him in English and a bit of Hebrew (and sends him to Hebrew school for his Judaic upbringing). The kid refuses to speak Spanish unless forced though he understands it just fine, happily natters away in English, and just had his Bar Mitzvah which he carried out in perfect Hebrew. It appears that the more his mother tries to -make- him "be" Latino, the more he wants to be "American" and takes pride in being Jewish. When she talks to him in Spanish, he answers in English.
I think the key is not to force children to do or be anything, but to make the richness of his or her cultural and ethnic heritage available in a "self-service" way on a daily basis.