Dear Abby recently had a column on this. A reader had sent in a letter because before her child was born they had been told it would be a girl, so they got a lot of pink clothes as gifts. Well the child turned out to be a boy, but they were using all the clothes they had gotten as gifts anyway. Her father-in-law was having a fit saying that dressing a boy in pink would make him gay or a cross dresser.
Abby had a lot of information regarding color choices and gender. It seems that throughout much of history, blue was viewed as a soft feminine color and was the traditional color of women. Red was the color for men as it was the color of blood. Because early dying processes werent as sophisticated as they were today, much of what was dyed red came out pink. Pink was viewed as light red and was considered masculine.
Throughout the 1800s and even into the early 1900s, blue was for girls and pink was for boys. She even quoted some etiquette books from the time that stated blue = girls, pink = boys. No one really had an explanation as to exactly when or how the colors got reversed.
Perhaps we are going back to the more historical use of pink and blue. I guess a man who wears pink is not so much a trendsetter as a traditionalist, going back to the older traditional use of color.