07/26/2013 09:53 am ET Updated Jul 26, 2013

'After Tiller' Trailer: Sundance Documentary Explores The Four Doctors Who Perform Late-Term Abortions

The new documentary "After Tiller" is guaranteed to stir up heated responses from all sides of the abortion discussion. The film centers on the remaining four doctors who perform late-term abortions -- a controversial practice that even some pro-choice advocates question. The Tiller referenced in the title is Dr. George Tiller, who also performed the operation following pregnancies' 20-week mark and who was killed by an anti-abortion activist in 2009.

"After Tiller" was an official selection for the 2013 Sundance Film Festival. It opens Sept. 20 in New York and Oct. 4 in Los Angeles.

Click here to watch a HuffPost Live discussion about "After Tiller," and check out a clip from the movie below.