Afraid of men?

I've just noticed lately that Katie has an anxiety about certain men.  At least 2 different mornings when I've driven her to the bus stop and she started to open the door to get out, she held back and actually got back in the car to wait until one man walking by got past us the one time, and a man out jogging passed us the other time.  Both of those gentlemen happened to be African-American. 

There has never been any prejudice in our home about African-Americans, or any other ethnicities.  Throughout all her school years her classes have always been at least 50% minorities and it has never seemed to phase her.  She has never mentioned the ethnicity of any of her friends, as if she doesn't even notice.  Then yesterday when we went to the store I sent her around the corner to hold one of the hall doors open for us coming through with our hands full.  After a minute I heard, "Mommy?" in a voice of concern, and as I came around the corner saw that a Latino man was coming through the door she was holding open and she was pressing herself back as far away from him as possible. 

This is an interesting contrast from the way she she sometimes acts around other men whose attention she seems to crave.  I've often been concerned about her lack of boundaries with other men at times, since I know it can make her vulnerable to be preyed upon when she craves male attention so much.  Something that merits more observation and discussion...