Anchor Baby is a slur used to describe Mexicans in a derogatory way. Children of parents who crossed the border illegally; A reference to their adulthood. At that time, they will be able to become the family "anchor" to legally bring in the rest of the family.
The word Anchor Baby is a racial slur that has been used historically to degrade and dehumanize mexicans. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to mexicans. If you are unsure about whether or not it is appropriate to use the word Anchor Baby, it is best to err on the side of caution and avoid using it in any situation.