There simply is no such thing as an anchor baby.
The claim is that people come to the US to have babies that will then allow them to stay in the US.
A baby gives a person absolutely no immigration benefits. The baby will have to be at least 21 years old, and have enough income to support the parents before he/she can petition the parents. One can immigrate legally a lot faster through employment, where the most severe backlog is currently at less than ten years.
Princeton University demographer Douglas Massey states that in 30 years studying Mexican immigration, he’s never interviewed a migrant who said they came to the United States just to get citizenship for their children.
“Mexicans do not come to have babies in the United States,” said Massey, who blames the tightening of the border in the 1990s for cutting off normal migration of men who used to come to work for a year or two and then go home. “They end up having babies in the United States because men can no longer circulate freely back and forth from homes in Mexico to jobs in the United States and husbands and wives quite understandably want to be together.”