Bill Donohue compares media reaction to the Planned Parenthood shooting to the 2012 shooting at the Family Research Council:

On August 15, 2012, a self-identified left-wing political activist entered the lobby of the Family Research Council armed with 100 rounds of ammunition. He told prosecutors that he intended to kill as many staff members as possible. He wound up shooting the security guard before being subdued. His rampage was inspired by the Southern Poverty Law Center’s decision to list the Family Research Center as a “hate group.”

On November 27, 2015, an armed crazed loner with no known political ties entered the offices of a Planned Parenthood center in Colorado Springs, Colorado and killed three people before being captured.

In the first three days following the Family Research Council shooting, the New York Times ran 2 stories totaling 935 words. In the first three days following the Planned Parenthood shooting, the New York Times ran 10 stories totaling 10,206 words, plus a blog post of 341 words. Which means it ran 935 words on the shooting at the conservative group and 10,547 words on the liberal group.

In the first three days following the Family Research Council shooting, the Washington Post ran 3 stories totaling 2,655 words. In the first three days following the Planned Parenthood shooting, the Washington Post ran 7 stories totaling 8,134 words, plus 11 blog posts totaling 11,873 words. Which means it ran 2,655 words on the shooting at the conservative group and 20,007 words on the liberal group.

Figures from the New York Times and the Washington Post combined:
Family Research Council: 5 stories = 3,590 words
Planned Parenthood: 17 stories and 12 blog posts = 30,554 words

Both newspapers are in the pro-abortion camp. If this doesn’t explain their bias, nothing does.