How can I know which nationality would have a baby born from parents from different nationalities?

  • The baby would have the nationality of the mother.
  • The baby would have the nationality of the father.
  • The baby would have the nationality of both mother and father.
  • The baby would have the nationality of the country where he or she born.
  • It depends on the laws of each country.

I think that the correct answer is the last one but I'm not sure; I suppose that in order to a baby to be acknowledged as a new born citizen in the country of the mom or the dad she or he should be registered in each country.

Where I can get more information about this? (I'm interested in the laws of UK and Spain).


To make things more complicated, one of the parents is from Catalonia. Now the relations between Catalonia (a Spanish region) and Spain are tense, and Catalonia would try to move towards independence from Spain... I don't know how this would affect to the nationality of the newborn.

  • I think Law would be a better fit. It may be too localized here (child with one parent from Spain and one from UK). It would definitely depend on each country's laws. (For example, I've known children in USA that had dual nationality as US & Brazilian because of parents, but at 18 they had to pick one and stick with it.)
    – user702
    Sep 29, 2015 at 2:03
  • @Erica I have no objections, thank you very much.
    – PaperBirdMaster
    Sep 29, 2015 at 5:24
  • @CreationEdge the US has no requirement to pick, so if those kids had to choose it was because of Brazilian law. Japan has a similar requirement, I think. The US used to have such a requirement, but the courts struck it down because it had been invented by the executive branch with no basis in legislation.
    – phoog
    Jun 20, 2016 at 4:31

2 Answers 2


The short answer, is "it's complicated". I can think of situations where any of the above options you listed might be true. (Another possible option is "The baby has no nationality at birth", and would therefore be considered stateless, and would fall under the birth country's rules regarding statelessness).

To find a definitive answer for your specific situation, I would start with Wikipedia:

Although Wikipedia is not authoritative, it does give you a good overview of the situation for both countries. There are then links to authoritative sources in each article.

In the case of a British and Spanish couple, their baby would probably be both British and Spanish at birth. Additionally, if the baby is born in a country (such as the US) which follows the jus soli rules, then the baby would also acquire the citizenship of their birth country.


It depends on the law of each country involved. Each country X can decide its own laws, and if the baby is a citizen of country X (or something else than a citizen; for example a country could give you certain rights that are less than citizenship) according to the laws of country X, then the baby has those rights. Other countries can do the same. No country X can make a law that says the baby is not citizen of country Y - well, they can make that kind of law, but country Y wouldn't care.

If all goes well the baby has one nationality. I knew one person who got her father's nationality, her mother's nationality, and the nationality of the country she was born (all three different). With bad luck, there is no nationality at all. Again, some country's laws may take this into account.

Some countries don't like dual or multiple nationalities. They can ask you to give up other nationalities if you want to keep theirs. Again, what the other country thinks about it is up to them. So things can be complicated.

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