Prime minister's wife Cherie Blair has said her children have been brought up Catholics to prevent them becoming "simply part of the Establishment".
Mrs Blair met earthquake survivors during her visit last month
The human rights lawyer said the choice was influenced by her faith's "bit of grit" in its social teachings and her children's "pretty privileged life".
Mrs Blair was interviewed by the Times magazine during a tour of Pakistan and Afghanistan last month.
She said her husband's job had given her a chance to "make a difference".
During the trip, which was made in her capacity as patron of the charity Breast Cancer Care, Mrs Blair met survivors of last year's earthquake, female politicians and other public figures.
"Sometimes just by going to these places and showing your face and talking about women's issues, at least you're both, hopefully, giving some sort of encouragement to those who are pushing those issues, and making people who are against those issues face up to the realities," she said.
Mrs Blair said one of the things that drew her to the prime minister was their interests in politics and spiritual matters.
Mrs Blair said when she was growing up being a Catholic "meant you were not part of the Establishment".
"And so, being from a fairly humble family myself, and knowing that my children are having a pretty privileged life, I don't want them to be simply part of the Establishment," she explained.
Mrs Blair unsuccessfully contested the 1983 general election as a Labour candidate in Thanet before quitting politics to focus on law.
She no longer harbours political ambitions of her own.
"I'm fascinated by politics... but, you know, you can change the world through the law, too, and that's the path I've chosen."
Mrs Blair was criticised for reportedly making £100,000 for a speaking tour in Australia last year but said the trip to South Asia was voluntary.
"I do these things all the time and don't get paid for them," she added.
She also gave an insight into Tony Blair's household skills.
"If anyone did change the fuse in our house, it was me, not Tony," she said.
"But I'm not claiming that I'm an electrician."
Fighting Breast Cancer - A Journey, Fiona Bruce's film following the Cherie Blair visit to Pakistan, is being shown on BBC News 24 at 2130 BST on Saturday and 1630 BST on Sunday.