I second Joseph's comment. And while it may not be other interviewers/HR personnel at this company asking such questions, however, this interviewer needs fixing.
"According to the EEOC, It Is Illegal to Ask a Candidate Questions About Their:
Race, Color, or National Origin.
Religion.
Sex, Gender Identity, or Sexual Orientation.
Pregnancy status.
Disability.
Age or Genetic Information.
Citizenship.
Marital Status or Number of Children."