Upvote:1
I reckon they can have. I have a friend of mine whose father is from Australia, his mom is British and he was born in Canada.
He has three passports from each country and the only problem he used to have is getting stopped in airports for further control but when he updated his passports to biometric, he never gets any suspicious looks from border control.
In a nutshell, it's possible to get multiple citizenship but it's not very common that's why it may attract attention.
Upvote:4
Citizenship and passport are issued by a sovereign country. They are generally accepted as valid by other countries which recognize that country. It is the issuing country which has to decide if other citizenships are acceptable.
For instance, the child of a French citizen and a Spanish citizen born in the US would be a French, Spanish, and US citizen. If he later wants to become a German citizen, Germany would require him to renounce the US citizenship, but not other EU citizenships.