When the crimes turn your stomach, you have no choice.  A defendant doesn't deserve an attorney who doesn't even want to sit in the same interview room at the jail with him/her.

Looking at dead body parts when I was a prosecutor at an autopsy during an investigation was different than when I was looking at photos of what my client had done to the victim  and confessed to having done long before I was appointed to represent him or her.  

The pictures of the dead 6-week old baby  were particularly unpleasant.

But, if the medical examiner says "blunt force trauma" you need to confirm that evidence exists of that  and not that the death might have been Sudden Infant Death Sydrome instead.
I had worse cases than that one, of course.