In a recent child development study, on gender-based preferences, there is new evidence that girls develop a preference for pink at about age 2, and while their prefernce may fade somewhat by age 5, the aversion to pink by boys stays steady between ages 2 and 5.
The study, by Lobue and Deloache in the Brittish Journal of Developmental Psychology , casts doubt on recent speculation that the preference has to do with an innate preference for louder colors, like pink. Indeed if there was such an innate preference we would likely see it reflected sooner.
In the study, toddlers indicated their preference by a paired choice of otherwise identical items, differing only in color. While this choice seems to overlap with a developmental phase that includes verbalization of some ability to distinguish genders verbally, it is still a long way from showing that these changes reflect acculturation.
The study did not look at a preference for blue, a preference that has not been shown to be very robust.
An interesting approach would be to control for language development, and look at the children of parents who themselves have differing views of gender equality, to see if these results are independent of these two factors.