- Both parents are illegal aliens (or rather, both parents cannot prove citizenship) - then the child isn't a citizen or has to go through a process. Easy enough.
- Both parents can prove citizenship. Child is automatically a citizen.
- Mother is citizen, but husband is not. OK, what now, does the mother have to go through immigration to get her own child, born in the US, citizenship? What if the process takes too long,will her baby be deported, but to where?
- Mother is citizen, but father is unknown. This is like #3, only even more complicated. Because if the father is a citizen, the child should be, but if he isn't, who knows.
- Father is citizen, but mother is not. Even more fun, since courts seem to side with a child staying with his or her mother, so maybe citizenship status should be the same as the mother's. But that seems unfair, especially if for #3 and #4 the child has citizenship.
- Mother and Father are unknown. This could happen in states with safe harbor laws (where babies can be left anonymously at hospitals.) So, does the baby have to go through immigration to be adopted?
- What if the parents are legal aliens? Will green cards require that you accept your future child is not a citizen?
- What about sperm / egg donors used for infertility? Usually parents have no idea who the donor is. Would the baby be a citizen if the birth mother is or only if the biological mother / father is?
The end result will be a very complicated set of laws which will probably end with a Supreme Court ruling and a new government bureaucracy.
[edited 7/19/10]
If the laws are the most lenient, that is every case except #1 is a citizen, then I would expect a large number of babies whose mothers suddenly have no idea who the father is.
If the law is closer to the UK's, then the mother's citizenship would be what counts. If the father refuses to sign the birth certificate, the child would not be a citizen if his/her mother wasn't. If the father was and signed, then the child would be a citizen. The problem is if someone signed the birth certificate as the father who wasn't really. Maybe the thought of having to pay child support would be enough to keep people honest.
If the laws are the strictest, that only #2 are citizens, I would expect a large out cry, but worse, a significant number of children who are not citizens of any country. America would still have to school them (because some school districts are forbidden to ask about immigration status). When they became adults, they would have no where legally to go. This is the same problem faced by children of illegal immigrants brought here illegally, but worse because they might not have another country to return to. (Especially if the mother is a native born us citizen, but the father is unknown.) These would end up being second class in the US, unable to legally hold a job. Even if there were a way for the babies to become citizens, it would probably involve a fee and many of the poorest could not afford it, or alternately, the taxpayer would foot the bill.
If not all children are born citizens of American, then who a baby's parents are is of utmost importance. If the government accepts a signed paper saying who the parents are, I suspect there would be a large number of people lying. The number of children being citizens wouldn't be significantly different than they are today. But if the law wants to be sure, it would require DNA testing to prove the baby is the child of the mother and father. To avoid profiling, every name that goes on the birth certificate will have to be tested. That will come at a cost, both economic and to our personal freedom. The poor couldn't afford the test, so either the taxpayers would pay for the test, or again, there would be a large number of children who live in the US, but are not citizens. I also wouldn't trust the government with a large database of DNA.
We need to take a good look at why people feel the laws should be changed. I am trying to be open minded (possibly failing :) ). I can understand not wanting to pay for children of illegal immigrants born in the US. I am not sure changing citizenship rules is the best way to address that issue. The cost of enforcing the change might be higher than just dealing with things how they are. The easiest, and best, solution is to leave things the way they are. Every baby born in America should be a citizen.