Editor's note: Watch more of Dr. Sanjay Gupta's interview with Melinda Gates on Sanjay Gupta MD on Saturday at 4:30 p.m. ET and Sunday at 7:30 a.m. ET.
(CNN) -- Responding to simmering controversy among Catholic bloggers about her new birth control program, Melinda Gates -- a practicing Catholic -- said she will not shrink from her role as an advocate for poor women.
"Part of what I do with the (Gates) Foundation comes from that incredible social justice I had growing up and belief that all lives, all lives are of equal value," said Gates during a recent interview with CNN chief medical correspondent Dr. Sanjay Gupta.
About the flak over her Catholicism she said: "We're not going to agree about everything, but that's OK."
Gates is promoting an ambitious family planning program -- which includes raising billions of dollars to provide contraceptives to 120 million women worldwide -- at the London Summit on Family Planning July 11.
While most Catholics, in the United States, at least, according to polls, seem to agree with Gates that contraception for women is not controversial, some Catholic bloggers are taking issue with the plan.
One blog in particular, LifeSiteNews.com, has frequently published diatribes against Gates, calling into question her faith, and calling her plan a "blatant attack on Catholic sexual morality."
As far as the broader Catholic church stance on the Gates program, CNN requested a comment from the United States Conference of Catholic Bishops, but did not get a response.
For her part, Gates is trying to deflect the controversy, and concentrate on what she describes as a real need for contraception to empower women.
"I think we made birth control and contraceptives way too political in the United States," said Gates, co-founder of the Bill & Melinda Gates Foundation. "I think if people understood that 200 million women want this around the world they would start to say, 'OK that makes sense.' ... We shouldn't make it such a political issue."
According to the Gates Foundation website, the focus of the family planning initiative will be on urban areas in sub-Saharan Africa and South Asia, areas where maternal and infant mortality rates are high and contraception use is low.
"Africa's the one place really in the world, for the most part, that contraceptives haven't been available and it's really been a crime," said Gates. "If you see what's happened in other countries that have had contraceptives, they use them first of all and the birth rates go down. ... The question is could it have come down even more quickly?"
Gates frequently cites research from a decades-long study in Bangladesh as a rationale for family planning. Given the ability to space out their children using birth control, women can begin what Gates calls a "virtuous economic cycle."
The study, started in the 1970s in Matlab, compared a group with access to contraception and birth-control education to a similar group that did not have access to those things.
"(In) the community that had access to contraceptives, the women chose to use them, the families grew up wealthier, fewer women died in childbirth," said Gates. "And what we're seeing happening with that is that it's playing out again all over the world. These small scale things you have in terms of giving a family the access leads to huge economic changes. "
To effect that cascade of economic change worldwide will take $4 billion, according to Gates. The London summit kicks off the Foundation's official campaign for support and funding for that effort.
No doubt, the family planning initiative will roll out despite Catholic protestations, and Gates says this is the issue for which she hopes to be remembered.
"I work on a broad set of foundation issues," said Gates. "But this one for me has really grasped my heart and my mind.
She added: "This will be my lifetime's work at the foundation."