There is now only one state in the US with a ban on same-sex marriage which is not being challenged in court.

South Dakota became the latest state with a legal challenge to a ban on same-sex marriage, as six couples filed a lawsuit there at the end of last week.

But North Dakota, in which voters approved a ban on same-sex couples marrying back in 2004, remains the only state without a challenge to its ban.

There are now over 30 US states with legal challenges against same-sex marriage bans. Another 19, and the District of Columbia allow same-sex couples to marry.

Couples in both Alaska and Montana also recently filed lawsuits challenging bans on same-sex marriage there.

Dozens of gay and lesbian couples in the US state of Pennsylvania rushed last week to obtain marriage licences, as a judge struck down its same-sex marriage ban, and the state said it would no longer defend it.

A 1996 state law had defined marriage as between one man and one woman, but in a ruling, US District Judge John Jones ruled that the ban was unconstitutional.

There soon may change, as according to reports, a lawsuit will soon be filed in the state of North Dakota to challenge its ban on same-sex marriage.

Voters in North Dakota approved a ban on same-sex marriage back in 2004, with 73%.