The March for Life in Washington on Friday renewed the annual impassioned call to end legalized abortion, 40 years after the Roe v. Wade decision. But this year, some Roman Catholic leaders and theologians are asking why so many of those who call themselves “pro-life” have been silent, or even opposed, when it comes to controlling the guns that have been used to kill and injure millions of Americans.

More than 60 Catholic priests, nuns, scholars and two former ambassadors to the Vatican sent a letter this week saying that if marchers and politicians truly want to defend life they should support “common-sense reforms to address the epidemic of gun violence in our nation.”

They called in particular on Catholic lawmakers, naming the House speaker, John A. Boehner, and Representative Paul D. Ryan of Wisconsin, both Republicans, as well as Senators Joe Donnelly of Indiana and Heidi Heitkamp of North Dakota, both Democrats, who they said have “A” ratings from the National Rifle Association, to stand up to the gun lobby. They urged support for legislation limiting the sale of military-style assault weapons and high-capacity magazines, like those used in the massacre last month at a school in Newtown, Conn.

“We’re addressing life,” said one of the signers, Thomas P. Melady, a Republican who served as ambassador to the Holy See under the first President George Bush. “I accept the Catholic teachings, which promote the sanctity of life from conception to natural death. And certainly the death of the 20 young kids and 6 adults in Newtown was not natural. Why can’t we take some steps with regards to these killings? These sophisticated weapons should be controlled.”