In Leadsom's interview on Thursday, she also told ITV News that she did not approve of the gay marriage legislation passed by Cameron.
"I believe that the love of same sex couples is every bit as valuable as that of opposite sex couples", she said.
Mr Cameron said from the North Atlantic Treaty Organisation summit in Warsaw: "So many people have taken advantage of it and there is now an enormous parliamentary majority for equal marriage".
"I don't agree with them, but. I would have preferred for civil partnerships to be available to heterosexual and gay couples and for marriage to have remained as a Christian service that was for men and women who wanted to commit in the eyes of God".
After reaching the shortlist, Ms Leadsom is committed to releasing details of her tax returns following newspaper reports over her tax arrangements.
"Everybody I've spoken to who does remember her says her CV doesn't match her role", said one of the sources. "The issue is one I have around the consequences, the very clear hurt caused to many Christians who felt that marriage in the church could only be between a man a woman".
She also hit back at those questioning her CV and insisted her claims about her pre-politics career had been "exactly accurate".
Andrea Leadsom, one of three candidates vying to become the next British prime minister, said she had given a full account of her past jobs on Thursday as some of her career credentials were called into doubt.
"I have not changed my CV".
DAVID Cameron has slapped down Tory leadership hopeful Andrea Leadsom with a warning not to try to reverse his landmark gay marriage law.
"None of my colleagues have misrepresented that I was managing investments on behalf of pensioners and savers; I was not a fund manager", the Energy Minister said. Typically in the United Kingdom financial industry, a senior investment officer manages client money.
Leadsom, who entered parliament in 2010, came second in the first round of voting among Conservative Party lawmakers on Tuesday with 66 votes, ahead of Gove with 48 and behind Home Secretary Theresa May with 165. However, Mr Cameron insisted the leadership election was a matter for the Conservative Party Board.
In an interview with the BBC on Sunday (Monday NZT), Leadsom spoke about her past "running enormous teams, small teams", running a start up business and being part of a huge bank.
In a freakish text message to fellow Tory MPs, Nick Boles said they "must work together" to stop Ms Leadsom being one of the two candidates on the ballot paper being sent to party members.
Having two women in the contest to decide the next prime minister will make it an honest campaign, former Conservative leader Iain Duncan Smith said. He said there was "no-one reporting to her in either role" while she was there.