US Vice-President Dick Cheney has revealed that his daughter Mary is expecting a baby boy. In an interview with ABC radio Mr Cheney said he was looking forward to the birth of his grandson.

Ms Cheney, 37, announced in December 2006 that she is pregnant. She has been with her partner Heather Poe for 15 years. She is due to give birth next month.

The Vice President has always been publicly supportive and protective of his younger child, who played a key role on his campaigns for the second-highest office in the land in 2000 and 2004.

During the interview he reiterated his view that legal rights for same sex couples are not a matter for the federal government:

“I think each state ought to have the capacity to decide how they want to handle those issues,” he said.

“I obviously think it’s important for us as a society to be tolerant and respectful of whatever arrangements people enter into.”

Mr Cheney has often spoken publicly of his love, admiration and respect for his lesbian daughter.

Ms Cheney’s partner Heather Poe often appears with the Vice Presidential family at official and political functions and events.

In January the Vice President told CNN that he is delighted about the birth of his sixth grandchild, and told presenter Wolf Blitzer he was out of order for bringing it up.

Mr Cheney was piqued that the TV host chose to discuss his younger daughter in the context of criticism from fundamentalist groups who think it is wrong for a lesbian to have a child.

Ms Cheney has also responded to attacks on her pregnancy.

Conservative and Christian groups have questioned whether Ms Cheney and Ms Poe will make suitable parents.

“When Heather and I decided to have a baby, I knew it wasn’t going to be the most popular decision,” said Ms Cheney, speaking at a panel discussion at a New York college in February.

“This is a baby. This is a blessing from God. It is not a political statement. It is not a prop to be used in a debate, on either side of a political issue. It is my child.”