During the latter part of the 1800s, pink and blue did begin to be associated with sex, but there was little agreement as to which color symbolized which gender. Opinions on the matter differed from country to country (pink for girls was the trend in France), and from region to region in the United States (pink for boys was popular in the Midwest), as the quote above, and these excerpts demonstrate:

via How to Wear Pink, Like a Man | The Art of Manliness.