There has always been a somewhat substantial argument for animal testing within the realms of medicine and science, but by no means is it humane, or even appropriate, to use animals as a resource when it comes to fragrances and cosmetics.
Peta recently released a list (http://www.mediapeta.com/peta/PDF/companiesdotest.pdf) of cosmetic companies who still test on animals, and Christina Aguilera's fragrances are, unfortunately, cited. This applies to both her self-titled perfume, and the newer release, 'Royal Desire'.
Aguilera has a new album about to hit stores around the world ('Lotus' Nov. 9), a milestone in her career that will be truly paramount to her success in the future. I suggest boycotting the album on the basis of her animal-tested fragrances. Furthermore, I urge you all to message Sony Music USA on the link below, identifying your lack of support as a result of Aguilera's immorally-sourced perfumes.