The US government treats the twin sons of a gay couple differently. The twins were born to an anonymous egg-donor and two fathers: one US citizen and one Israeli citizen. The couple married in Canada, where the twins were born. Upon applying to the US Embassy for the twins’ citizenship, and submitting their DNA, only the child who bore the DNA of the US citizen was eligible for the country’s citizenship. According to the lawsuit the couple submitted, both boys should have been eligible for citizenship since they each had a US citizen parent. Furthermore, it has been argued that this constitutes discrimination because children from a heterosexual marriage would have been different.

Recently, a similar approach was applied in the case of an American-Italian lesbian couple seeking citizenship for their babies. Only the citizenship of the baby that had the US mother was recognised.

Read more about these cases in The Guardian, BBC News and Slate.
For details of current and past citizenship legislation in the US, check out our country profile pages.