It probably comes from the fact that many babies are born with a nice pink color that shows that they are in good health.

VOA: special.2009.11.15

The Women's Basketball Coaches Association gave permission for teams to wear the color pink to honor Coach Yow's work in educating people about breast cancer.

VOA: special.2009.03.29

Now it was not just any old cake. It came in the round cake pans, and I baked it, but then I attempted to cut out a heart and used pink icing and decorated it.

VOA: special.2010.02.08