The ad, which stars Tebow and his mother, Pam, recounts Her decision not to terminate her pregnancy despite having had medical treatment for amoebic dysentery. Doctors had advised her to end the pregnancy because the medications threatened the fetus. She ignored their advice and gave birth to Tim Tebow in 1987.
"I know some people won't agree with it," said Tebow of the 30-second ad at a press conference in Mobile, Ala., last month. "But I think they can at least respect that I stand up for what I believe. I've always been very convicted of [his views on abortion] because that's the reason I'm here, because my mom was a very courageous woman."
Television networks have traditionally shied away from ads advocating positions on a controversial issue, and ads on abortion, Advertising Age's Garfield said, are "right at the top of the list."
So why would this particular ad make the cut?
A source at CBS told ABC News last week that the the words "abortion" and "pro-life" did not appear anywhere in the ad.
"My best guess is they looked at the text of the ad and not the overall context and said 'The ad itself is quite benign, so let's use it," Garfield said.
CBS released an official statement about the ad last week.
"We have for some time moderated our approach to advocacy submissions after it became apparent that our stance did not reflect public sentiment or industry norms on the issue. In fact, most media outlets have accepted advocacy ads for some time," the company said. "At CBS, our standards and practices process continues to adhere to a process that ensures all ads -- on all sides of an issue -- are appropriate for air."