This question is for you to ask the interviewer. This a trick by you. First, you want to know what the gender ratio is (ask first), but you also want to show that you're a fan of diversity and embrace it. Diversity, besides being a really good thing and important, is a big, big, deal, and just by the way you ask this question will reveal to your interviewer that you're well on-board with it and see it as a good thing and something you find attractive.

Above all, people selecting applicants want someone who gives them the following indications:
-That they can rise to challenge, even during the most challengeable times.
-That they can stay the course and finish the program. Accepting a candidate is a big investment, and one dropping out represents a huge loss that cannot be recouped.
-That the things important to the program, e.g., diversity, empathy, etc., are just as important to the applicant.
-That the applicant is stable, that is, is consistent in his/her ethics/morality.
-That the applicant isn't just 'book knowledge,' but has the attributes traditionally see as necessary in the practice of medicine; that he/she is a people person and dedicated to the human connection in caring for patients.