Originally Posted by
GUWonder
I'm taking "right of birth" to mean a right conveyed via birth, whether due to lineage, place of birth or circumstances applicable at time of birth.
Perhaps 7 at least: presuming: the 4 grandparents, 2 parents, and the place of birth convey separate rights to separate citizenships as a right of birth; and none of the acquisitions of citizenship by right of birth conflict with acquisition of other citizenship(s).
It's far more difficult to find people who were born entitled to more than 4 citizenships as a right of birth than it is to find people who ended up with 5 citizenships or more.
I agree that the likelihood grows smaller the larger the number is, but I do know a couple where each of them has three citizenships, none of which coincide. Four of those six total citizenships were acquired after birth (that is not from their parents). They both currently live in yet another country, so that if they have a child in that country (a jus solis country), the child has the potential for 7 nationalities. But just imagine if those two people had parents from two different countries - that would have added another two potential nationalities for 9!