The judge wouldn't question an allegedly improper peremptory challenge in open court. Objections to challenges are made at sidebar. Under Batson a minority defendant must have a venire that includes at least another minority. If the prosecution uses challenges to remove all of the minorities from the prospective jury, the defendant then makes a Batson challenge where the prosecutor must offer racially neutral reasons for striking the minority members.

I don't think that attorneys would ask sexual orientation questions in a general voir dire, but it is possible that jury questionnaires may include a block to check at the option of the prospective juror. For the most part a person's orientation won't come into play. even in cases where the offense involves collateral issues that touch on orientation, most of the voir dire questions would seek to determine whether a prospective juror may possess a belief or bias that would inhibit him from determining the facts of the case impartially.