Season 5 is now on its second half, and as more and more babies are born with deformities, Dr. Patrick Turner is about to find out the drug that causes the malformations.

The next episodes will show the time when Thalidomide is pointed to cause the limb formation defects in new born babies. Radio Times spoke with actor Stephen McGann, who plays Dr. Turner in the series, and he shared the dilemma his character is about to face, knowing that in the previous season, he administered the drug to one his patients.

McGann shared that Dr. Turner will be very sad upon discovering the truth and feel "The shock, the appalling sense of responsibility for those people in our care," he added, "I think doctors took a sort of collective guilt as a profession."

He also shared how privileged it feels to take part in a storyline that is based on a controversial period that happened in the 1960s, which he described as an amazing time for medical discoveries. He said "It's challenging for all of us. We all felt the responsibility was incredible. On the set it's been really moving."

Meanwhile, BBC has posted the synopsis for "Call the Midwife" season 5's fifth episode which airs on Feb. 14. It says, "With modern advances starting to change things for the better, even medical professionals like Dr Turner and Shelagh are forced to consider their own lifestyles. As they fight for better respiratory health for their patients, Timothy realises the risks his parents are running by continuing to smoke. "

The episode will also show Violet and Fred figure in a domestic circumstance when the former's back is injured. The episode will also feature a new family whose mother, Roseanne, has difficulties dealing with her past. Nurse Crane steps in to help her.