Getting a Chica "Pregnant"
As is often the case, things work differently in Mexico than in the U.S. In the US a woman enters the father's name on the birth certificate. In Mexico a man must sign the birth certificate. Or following a confirming DNA test the court can order his name placed on the birth certificate.
Only the results of designated labs are accepted by Mexican courts. The woman must pay all lab fees in advance when requesting the court to order a man to take a DNA test. Four years ago the fee was (approx.) US $600.00. Consequently not too many chicas take legal action to get the court to order a DNA test.
Mexican courts typically order child support of (approx.) US $200 to $300 per month. Many Mexican men (like many guys in the US) are dead beat dads. However, in Mexico a man can be put in prison for failure to pay child support--and he stays there until it's paid (or the woman relents). That's right: it's a debtor prison for dead beat dads in Mexico.
If the father is a US citizen a Mexican mother can often use US courts to determine paternity and obtain child support. It all depends on the state in which a man resides as there is a compact that many states have entered into with Mexico in this area. (Again, it is not a treaty between the US gov't and Mexico but an agreement--or whatever legal term is applicable--between individual states in the US and Mexico.) California is one of the states in which a Mexican mother can use the courts to determine paternity and collect child support.
If a man lives in California a savy chica can contact the local DA. The DA will find the man and get a court order from a California court ordering him to take a DNA test. If the DNA test is positive the chica can then use California courts to collect child support.
If a child has a parent who is a US citizen the child when he/she reaches the age of majority can obtain US citizenship. Or the child's guardian, while the child is a minor, can apply for US citizenship on behalf of the child. Either way citizenship is always granted--after all the necessary application forms are correctly submitted.
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How do I know this? The (Mexican) father of one of gf's kids didn't want to take responsibility for his son. I also know a Gringo who thought he was safe as long as he stayed out of Mexico.
Some guys are successful in avoiding paying child support. Others aren't.
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Sadly, many chicas in the ZN (like many/most civilian chicas in TJ) don't use birth control. I know a chica who used to work at Valantina. She now has a two year old son--and has no idea who is the father. Her situation is far from unique.