The US Supreme Court is set to consider the issue of same-sex marriage for the first time after it agreed last week to review two challenges to federal and state laws that define marriage as a union between a man and a woman.

It said it would review the ruling which overturned California’s Proposition 8, which banned same-sex marriage. This was passed in 2008 by popular ballot but was later overturned by the Ninth Circut Court of Appeals.

Depending on how it goes, the Supreme Court’s decision to rule on Proposition 8 will either lead to all fifty states being forced to grant marriages to people of the same sex or else will leave it in the hands of the individual states.

Out of 36 states which have voted on the issue, 32 have upheld the traditional definition of marriage.

The nine justices also announced they would rule on the federal Defence of Marriage Act (DOMA).

DOMA, which was signed by President Bill Clinton in 1996, defines marriage as being between a man a woman and it allows states where same-sex marriage is illegal to refuse to recognise same-sex marriages contracted in other states.

Both cases are likely to be argued before the court in March while their rulings are expected in June.

John Eastman, chairman of the National Organisation for Marriage, one of the leading groups defending traditional marriage, said the court had sent “a strong signal” that it would uphold states’ rights to uphold man/woman marriage.

The court’s decision to take on Proposition 8 will be the last stop for a legal battle that began in 2008, when California’s own Supreme Court ruled that gay and lesbian couples had the right to marry under the state’s constitution and thereby quashed the popular vote.

Pro-family groups took the issue to a public vote by holding a referendum to alter the constitution to explicitly ban same-sex marriage.