A popular fertility app that helps women track their cycles to aid them in planning — or avoiding — pregnancies is being quietly bankrolled by an anti-gay, pro-Catholic group battling reproductive rights for women, The Guardian reported.

While posing as a tool helping women to make reproductive choices, the app attacks certain forms of birth control as unsafe and unreliable, according to the newspaper. That may dissuade women from using certain reliable methods, which could result in unwanted pregnancies.

The Femm app’s literature questions the safety and effectiveness of hormonal birth control, such as pills or a patch, currently among the more reliable forms of birth control for women, according to the federal Centers for Disease Control and Prevention. Tracking cycles, which is promoted by the Femm app, is the least reliable, according to the CDC.

The Femm app, which is run by the not-for-profit Femm Foundation, has been downloaded some 400,000 times by users all over the globe, including the U.S.

Among the private donors supporting the app is the Chiaroscuro Foundation, a charity backed by Catholic hedge funder and anti-abortion activist Sean Fieler, a big supporter of Vice President Mike Pence, The Guardian reported. The foundation donated $1.79 million to Femm developers over the last three years, according to the newspaper. App users are not informed of the anti-abortion beliefs of funders.

The app also collects information about sex and menstruation from users.

Two of the app’s medical advisers are not licensed to practice in the U.S., according to The Guardian.

Anna Halpine, CEO of the Femm Foundation, told The Guardian that the beliefs of the group and its funders are irrelevant because the app is “not dealing with the question of abortion.” Femm has “never commented on the abortion issue,” she said.

Femm posted a lengthier statement Thursday on its website responding to The Guardian article. It said that donors “understand the importance of non-pharma” research and that Femm is seeking to provide “more choices” for women.

Check out the video above to see some of the challenges of cycle-tracking as an effective form of birth control.