North Carolina has voted for Amendment One, a change to the state’s constitution that bans civil unions and same-sex marriages.
The south-eastern American state voted Tuesday (8 May) to outlaw same-sex unions, which were already prohibited.
Supporters pushed for the constitutional amendment, stating there was a need for protection against any further legal challenges.
As the writing of the legislation is vague, it is unknown whether the amendment will also outstrip the rights of unmarried co-habiting straight couples.
A spokesman for President Barack Obama said he was ‘disappointed by the vote’, saying it was discriminatory towards gays and lesbians.
He said: 'If it passes, it won’t change North Carolina’s law on marriage. What it will change is North Carolina’s ability to keep good businesses, attract new jobs, and attract and keep talented entrepreneurs.
‘If it passes, your ability to keep those businesses, get those jobs, and get those talented entrepreneurs will be weakened. And losing even one job to Amendment One is too big of a risk.
He added: 'Its passage will also take away health insurance from children and could even take away domestic violence protections from women.
'So the real effect of the law is not to keep the traditional definition of marriage, you’ve already done that. The real effect of the law will be to hurt families and drive away jobs. North Carolina can do better.'
The amendment was supported by three times married and former Republican Presidential nominee Newt Gingrich who said he was urging people to ‘vote for preserving a very basic institution.’
North Carolina governor Beverley Perdue said ‘writing discrimination into North Carolina’s constitution is just plain wrong.’
'This will harm the stability and security of North Carolina’s families like never before,' the governor warned.
She said: 'Our constitution was written to guarantee rights, not to take them away.’
Voters approved the amendment by a 61%-39% margin, according to unofficial returns from the State Board of Elections.