Too Sensitive or Appropriately Annoyed?

I was sitting at Starbucks today doing my homework during lunch. Apparently they are having some kind of hiring event at this particular location. One of the managers interviewed a few people at the table next to mine. During one of the interviews, the male manager asked the young female interviewee, "Are you pregnant?" Her response was, "I don't think so." He then said, "Do you plan on getting pregnant?" I couldn't hear what she said exactly but from the the few words I caught and from the body language, it seemed as though she answered "no" in some way and the manager seemed satisfied with her response.

This girl looked about 17, and she appeared to be unmarried (no ring). Asking this question seems inappropriate to me, and I seem to think that such questioning by a perspective employer is a type of sexual harassment. Isn't it? And if it isn't, it should be. I heard the same manager interview 2 guys and that question never came up. I was shocked and appalled. I even turned sharply towards him and looked right at him when we asked. I'm not sure he noticed but I did what I could to make him feel guilty.

I am not one to make big issues about small-ish gender differences, and I CAN see the manager's concern...Pragmatically speaking, hiring a pregnant lady could be inconvenient. But I certainly don't think it's right to treat men and women in the work place differently, and I don't think it's right to ask this question, especially in an interview.

Maybe I"m just being sensitive because I am tired of being told by my boss "One day you'll have to decide if you're going to be a mommy or a career woman." I HATE that conversation.